Work through it in order

1. Open in WebView: from the source’s page in Mihon, choose Open in WebView and complete any verification. Passing once usually leaves cookies that let the app through afterwards.
2. Check the site in a browser: if the source is down or region-blocked in a normal browser too, no app setting will fix it — wait, or migrate affected titles to another source.
3. Stop hammering: 403s during a global library update or mass download often mean rate limiting. Wait an hour, then update in smaller batches (library update diagnosis).
4. Try a different network: some IPs (shared VPN exits, campus networks) are blocklisted by sources. Testing on mobile data vs Wi-Fi tells you if your IP is the problem. A reputable VPN can help when your own IP is flagged — but a flagged VPN exit makes it worse; see VPN notes.
5. Update the extension: sites change their checks; extension updates under Browse → Extensions frequently restore access.

About DNS

Search data shows readers also hit this error alongside DNS problems: if a source fails on your home network but works on mobile data, your ISP’s DNS or a DNS-level filter may be interfering. Mihon’s advanced settings include DNS-over-HTTPS options, and switching the device DNS to a public resolver is a reasonable test — if the error vanishes, it was the network path, not the source.

What 403 is not

• Not a sign your account is banned — 403 happens before accounts are involved, at the door.
• Not fixable by reinstalling Mihon or clearing your whole library. Do not nuke your setup for a server-side refusal.
• Not a reason to install “403 bypass” extensions from forums; none exist legitimately.

Related: all troubleshooting guides · no extensions found

Fix 1 — Update Android System WebView

Mihon’s WebView is the system component, not something inside the APK. Open the Play Store, update Android System WebView (and Chrome, if it provides your WebView), then force-close and reopen Mihon. Blank pages and endless spinners after an Android update are classically this.

Fix 2 — Clear WebView cookies and data in Mihon

1. In Mihon, go to Settings → Advanced and find the option to clear WebView data / cookies.
2. Clear it, then open the source and log in fresh through Open in WebView.
3. Complete any verification (checkbox, 2FA) in that same WebView session — switching to a full browser and back breaks the cookie handoff.

Fix 3 — Tracker logins failing with Cloudflare

If the failing login is a tracker (Kitsu is the documented example) and the error mentions bypassing Cloudflare, update Mihon: 0.21.2’s changelog says “Fixed Kitsu login failing with ‘Failed to bypass Cloudflare'”. The general version of that problem is covered in the Cloudflare guide.

Still looping? Check these

• A VPN, private DNS, or ad-blocking DNS can strip the cookies the login sets; test once without it.
• Date/time set manually (not automatic) breaks secure logins — set the device clock to automatic.
• Some sources require logging in on their real website first (account creation and age/region confirmations cannot always happen inside a WebView). Create the account in a browser, then log in inside Mihon.
• If the page renders but buttons do nothing, the site may require a newer WebView than your device can install — an old-Android limitation with no in-app fix.

Related: all troubleshooting guides · tracking setup

Signature conflict — the classic Tachiyomi/Mihon clash

Android refuses to install an app over an existing one if the signatures differ. Tachiyomi’s package is eu.kanade.tachiyomi; Mihon’s is app.mihon, and its FOSS build is app.mihon.foss — those three coexist fine. Conflicts appear when a fork or a modified build shares a package name with different signing: for example a modded “Tachiyomi” from a random site, then the genuine build on top. Fix: back up inside the installed app first (backup guide), uninstall the conflicting copy, then install the genuine APK and restore.

Corrupted or wrong file — verify before retrying

1. Re-download the file; a cut-off download is the simplest cause of parse errors.
2. Verify the SHA-256. Our Mihon page lists the official v0.21.2 hashes for every build, and the Tachiyomi page lists the archive-published hash for the universal package. A mismatch means do not install that file.
3. Pick the right architecture: if you grabbed an x86 build for an ARM phone (or vice versa), use the universal APK instead — it contains all architectures.

Android version too old

Parse errors on old devices are often just the version floor: Mihon 0.21.x requires Android 8.0 (API 26). On Android 6/7 the install cannot proceed — Tachiyomi 0.15.3 (Android 6.0+) still installs there, which is one reason legacy users keep it. There is no workaround that makes a modern Mihon run on Android 6/7.

Other quick checks

• Free up storage: installs fail silently when the device is nearly full.
• If Play Protect blocks the install with a warning, do not just override it — verify the hash first (above). A matching hash from the official GitHub release is the real all-clear.
• Installing via Shizuku or ADB shows the true error code; the installer option in Mihon is covered in our Shizuku guide.

Related: all troubleshooting guides

What the changelogs actually say

• 0.21.1: fixed “the app staying on the updating screen for good when updating its data failed”, plus crashes on launch on some Samsung devices (Android 9–11) and updates from 0.20.x taking hours on duplicate-heavy libraries.
• 0.21.2: fixed “updating from v0.20.x failing on some older databases, which left the app on the updating screen or crashing on launch”.

Recovery steps

1. Force-stop Mihon and reopen it once. A database migration that was interrupted sometimes completes on the second launch.
2. Install v0.21.2 over your current app using the official GitHub APK (download page with hashes) — installing the same package (app.mihon) over itself keeps your data. Verify the file’s SHA-256 against the table there.
3. Be patient on the first launch if your library is huge or full of duplicates; the migration is genuinely slow on old databases. Charge the phone and leave it.
4. If it still will not open: clear the app cache only (system Settings → Apps → Mihon → Storage → Clear cache). Do not clear data/storage — that deletes the library database.
5. Last resort: if you have a .tachibk backup, uninstall, install 0.21.2 fresh, and restore (restore guide). This is exactly why backups matter before upgrades.

Avoid it next time

Export a backup before every major upgrade (the Mihon team prints the same advice in the 0.21 release notes), and avoid skipping several major versions at once — step through the current stable instead. If the failure appeared while restoring rather than upgrading, see decryption failed instead.

Related: all troubleshooting guides

Downloads stall or stop when the screen is off

This is Android battery optimization killing the download service. Set Mihon to Unrestricted battery use in system settings, and disable any “battery saver” for the download session. If downloads only run while the app is open on screen, this was your problem.

Downloads error instantly

• Storage access lost: after system updates or folder moves, Mihon can lose permission to its storage location. Re-select it under Settings → Advanced → Storage location and grant access again.
• Out of space: manga chapters add up — check free space, and clear chapters you have finished (managing downloads).
• Corrupt queue entry: cancel the failed item in the Downloads queue and queue the chapter again.

Downloads fail for one source only

Open the source and try to read a chapter online. If reading also fails with 403 or a Cloudflare page, the downloads are failing for the same reason — follow 403 fixes or Cloudflare fixes. If reading works but downloads fail, update the extension; download paths break more often than reading paths when a site changes.

Downloads crawl or time out on mobile data

• Check for a Wi-Fi-only setting in download options that pauses the queue on mobile data.
• A VPN or DNS filter can throttle image hosts; test one chapter with it off (and see our VPN notes for networks that interfere).
• Download fewer chapters at once — parallel queues trip source rate limits, which look identical to slow downloads.

Related: all troubleshooting guides · offline reading guide

Read the failure before fixing it

• Only some titles fail — those titles’ source changed something. Open one failing title: if the source itself will not load, the extension needs an update or the series needs migrating to another source.
• A whole source fails — check for an extension update under Browse → Extensions; if none exists and the site errors in WebView too, the source is down or blocking (see 403 / Cloudflare).
• Everything fails with timeouts — network problem or rate limiting. Try a different network and a smaller update batch.

The battery setting that fixes “update just stops”

Android aggressively stops background apps. If updates start fine and quietly die, set Mihon’s battery usage to Unrestricted in the system app settings, and keep the phone charging during very large first updates. The same setting fixes stalled downloads — see downloads failing.

Make updates smaller and smarter

• Restrict automatic library updates to the categories you are actively reading (Settings → Library).
• Exclude completed series and series on long hiatus from global updates — they waste requests and trigger rate limits.
• Update extensions before a big library run, not after: outdated extensions are the most common per-source failure.

Duplicates and old databases

Libraries carried since Tachiyomi days can contain duplicate entries that slow updates dramatically — Mihon 0.21.1 fixed updates taking up to hours on duplicate-heavy libraries from 0.20.x, and tidying duplicates still helps. See library cleanup. If an update after an app upgrade leaves Mihon frozen on its updating screen instead, that is a separate known issue with its own page: stuck on updating screen.

Related: all troubleshooting guides

If you already added a repository and the list is still empty

1. Pull to refresh on the Extensions tab; a newly added repository does not always populate until refreshed.
2. Check the URL character by character. A trailing space, a missing .json, or choosing the wrong index file all produce a silent empty list. Remove the repository and re-add it by copy-paste, not by typing.
3. Check the network. Repository indexes are hosted on GitHub; networks that block GitHub (school, work, some countries’ ISPs) leave the list empty. Test on a different network or with a DNS change.
4. Update Mihon. Repository formats changed in 0.20 (“repos” became “stores”) and again with the tachiyomix 1.6 extension format; an old app can fail to read a current index. Current release: v0.21.2 (download page).
5. Confirm you are looking in the right place: installed sources live under the Sources tab; the Extensions tab is the install list. A source you installed but haven’t used sits in Sources, possibly below the fold under its language section.

Extensions installed, but a source shows an empty catalog

That is a different layer of problem: the extension installed fine, but the source site is challenging or has changed. Work through 403 errors and Cloudflare failures for that case.

A safety note

Only add repositories whose URL you copied from a source you trust, character for character. Fake “Mihon extension” pages with lookalike repository URLs are a real thing; extensions are executable code on your phone. The repository guide explains the trust prompt Android shows for new repositories.

Related: all troubleshooting guides · migrating from Tachiyomi

Why it happens

Sources and trackers sit behind Cloudflare, which challenges visitors it cannot verify. An app is not a full browser, so the challenge sometimes cannot complete automatically. Mihon’s 0.21.2 changelog lists the fix plainly: “Fixed Kitsu login failing with ‘Failed to bypass Cloudflare’.” The same release also fixed slowdowns when many requests hit a Cloudflare challenge at once — a burst of library updates can trigger exactly that.

The fixes, in order

1. Update Mihon to 0.21.2+ from the official GitHub release (download page with file hashes). If your error is the Kitsu/tracker login one, this is the fix, full stop.
2. Complete the check in WebView: open the failing source, choose Open in WebView from its menu, and solve the Cloudflare check like a human in a browser. Mihon keeps the resulting cookies, and the source usually works afterwards.
3. Slow down bulk actions: if the error appears during a global library update, update in smaller batches per category instead of everything at once.
4. Check your network path: some VPN exits, DNS filters and school/work networks are flagged aggressively by Cloudflare. Try a different network (or a reputable VPN, see VPN guide) to confirm the network is the trigger.
5. Wait it out: repeated failed attempts can get your IP temporarily challenged harder. Give it an hour rather than hammering refresh.

What not to do

Do not install “Cloudflare bypass” extensions or APKs from forums — there is no such legitimate tool, and lookalike downloads are a common malware route. Do not change Mihon’s user agent to random strings found online; the default modern user agent works, and random strings often make challenges worse. Persistent 403s on a single source (rather than a Cloudflare page) are a different error: see HTTP 403 source errors.

Related: all troubleshooting guides · WebView login problems

Fix 1 — Update Mihon first

Backup formats evolve with the app. Before anything else, update to the current release (v0.21.2, from the official GitHub — see our Mihon download page with checksums) and try the restore again. This one step resolves most cases where the backup was created on a newer version than the app trying to open it. Note the direction of the deadline: 0.21.x is the last major line that restores Tachiyomi .tachibk files directly, so the restoring app being too old is the common failure, not too new.

Fix 2 — Check the file itself

• Re-copy the backup from its original location; a transfer interrupted halfway leaves a file that looks right but fails to decrypt.
• Do not rename the file extension or open/edit the file in another app — any change to its contents breaks it.
• If you keep dated copies (you should — see backup habits), try the previous copy: if the older one restores, the newest file is the damaged one.

Fix 3 — Restore in the app that made the backup

Backups made by forks (TachiyomiSY, TachiyomiAZ, Aniyomi and others) are usually compatible with Mihon — but not always, especially across big version jumps. If a fork’s backup refuses to restore in Mihon, restore it in that fork first, confirm the library is intact, then export a fresh backup from the fork’s current version and restore that in Mihon.

Fix 4 — Re-export from the old app

If the old app still runs, this is the most reliable path of all: open Tachiyomi (or your fork), create a brand-new backup with every category ticked, copy it over untouched, and restore. Our migration guide walks the full sequence, including adding extension repositories before restoring so entries link correctly.

What not to do

• Do not uninstall the old app or clear its data until a restore has succeeded and you have opened a few chapters in Mihon — your only copy of the library may be inside it.
• Do not download “backup fixer” tools or upload your .tachibk to websites that promise to repair it. The file contains your library and tracking data; treat it like a password file.
• Do not factory-reset or change phones mid-troubleshooting.

Still stuck? If the app itself hangs while processing the restore, see stuck on the updating screen. Related: all troubleshooting guides.