ProtonMail Not Loading or Syncing

Applies to: Proton Mail web, Proton Mail app (iOS/Android), Proton Mail Bridge

1. Web app stuck loading

1. Hard refresh — Ctrl+Shift+R or Cmd+Shift+R.
2. Try a private window. Ad blockers and VPN extensions in particular are one of the more common causes I've run into for Proton's encrypted interface just refusing to load.
3. Check status.proton.me before digging further — sometimes it's genuinely on their end.

2. Mobile app not syncing

1. Pull down to refresh the inbox manually.
2. Check that background app refresh is enabled for Proton Mail in your phone's system settings, not just inside the app itself — this one's easy to miss.
3. Still stale after a manual refresh? Log out and back in.

3. Proton Mail Bridge (desktop clients like Outlook/Thunderbird via Proton)

Because everything's encrypted, third-party desktop clients connect through the local Bridge app rather than Proton directly. Worth understanding, because it changes where you should actually look when something's off.

1. Confirm Bridge is actually running in the background — check your system tray or menu bar first.
2. Reconnect the account in Bridge if it shows disconnected.
3. Your mail client needs the Bridge-generated password, not your normal Proton login. If you're not sure which one you're using, just regenerate it from Bridge.

If Bridge specifically won't connect at all — not just showing stale mail, but genuinely refusing to reach Proton's servers — two things to check before anything else:

• A VPN with ad/malware blocking enabled can interfere with Bridge's connection. In Bridge → Settings → Advanced Settings, try disabling "Alternative Routing," or temporarily turn the VPN off and restart Bridge to confirm that's the cause.
• Antivirus or firewall software blocking Bridge specifically. On Windows, the default install path is C:\Program Files\Proton AG\Proton Mail Bridge\proton-bridge.exe — add an exception for that path (and its Updates folder) in both your antivirus and Windows Firewall settings.

4. "Decrypting message" errors

Rare, in my experience, and it usually clears up after a resync. If it keeps recurring, it can point to a key sync issue between devices — I'd go straight to Proton support rather than trying to fix keys manually. Mishandling encryption keys can make mail permanently unreadable, and that's not a risk worth taking on your own.