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Folder polling is not reliable any more #7839
Description
Checklist
- I have used the search function to see if someone else has already submitted the same bug report.
- I will describe the problem with as much detail as possible.
App version
6.803 (still happening with Thunderbird for Android 22.0)
Where did you get the app from?
Google Play
Android version
14 (still happening with 17)
Device model
Pixel 7a
Steps to reproduce
- Configure the app to poll for new emails every 15 minutes.
- Turn off the phone screen and do not use the phone.
- Send yourself an email from another device.
- Wait for the notification.
Expected behavior
Notifications for new emails should be shown not more than 15 minutes later.
Actual behavior
No notifications for new emails are shown. As far I can tell it's not just that the notification is missing, but the app doesn't even poll for emails.
Sometimes I get the emails when I wake up the phone (turn the screen on).
Sometimes I need to unlock the phone to get them.
Sometimes I even need to open the app. In those cases I see that no new emails are shown, then the progress indicator line on top of the email list shows up, and only then the emails are polled.
This problem started a few weeks ago. Maybe with the update to version 6.802. Maybe it was also an Android update (e.g. April or May update) that caused it.
The Android setting/permission for battery usage of the app is already set to "allow background usage" and "not limited" (my translations, I'm not sure on the official english wording of those settings).
Logs
No response
Activity
Xavron commentedon Jun 17, 2024
There's actually a lot of possibilities here and some are device.
Android 14 for instance also has a separated location of sleeping and deep sleeping apps. The issue post here doesn't specify.
Android also has various things at play including for example attempts at forcing apps to not run on exact time as it uses more battery by keeping the device from deep sleep.
Android manufacturers can at times be overly aggressive and kill background apps no matter what you do.
The email service that is used may timeout or have other connection issues or limits causing it to not be on exact time or not happen.
Apps can do things like wake locks but even that is receiving some force blocks by Android so not all situations will work.
Its difficult to say what the app can or can't do in being exact and there will be cases where it may not be possible. Conversely, Google won't really allow this to happen to their own app which is another thing entirely lol.
But, all 3rd party developer Android apps are going through this. Some get by better but many see this type of problem.
cremor commentedon Jun 17, 2024
Where can I find both of those settings?
I use 3 email addresses of 2 different providers (one is Gmail). All show the same problem.
Xavron commentedon Jun 17, 2024
The Android 14 new feature should be in Android Settings > Battery > Background usage limits > sleeping / deep sleeping apps. Android 14 will auto add apps as time goes by. If its the one you were talking about then not allowing it in there is a good idea as it definitely can and will break apps.
cremor commentedon Jun 20, 2024
I don't have such an menu entry in the battery settings. I've also looked through all sub-menus and could only find the app specific settings which are already set to unrestricted background usage.
Xavron commentedon Sep 14, 2024
It could be at a different location in Android settings on that device. Perhaps do a settings search for it?
cremor commentedon Sep 14, 2024
Searching the settings menu for "background", "sleep", "standby" etc. doesn't bring up anything. But that doesn't say much, because there is for sure a "allow background usage" setting (that I have already turned on, as written in the initial post). So that search function seems useless.
I've also searched the settings manually and couldn't find anything that I haven't already set to allow anything for K-9.
w6a8w8 commentedon Oct 25, 2024
I'm encountering a similar issue on Android 12. I have polling set to every 2 hours for two different accounts, with background activity and autostart fully allowed. Despite these settings, I often miss notifications for new emails. Even after opening the app, emails don't sync automatically—I have to manually pull down to refresh. Sometimes emails received over 4 hours prior aren't displayed until I do this, suggesting that sync fails at least twice in a row. Any insights or fixes would be appreciated.
rienheuver commentedon Jun 10, 2025
I'm running into this as well. Oneplus 9 with original OS. I just synced by manually pulling down in the app and it fetched mails from over 24h ago. My interval is set to 15min.
cremor commentedon Mar 13, 2026
This problem still exists in Thunderbird for Android 16.1 with Android 16. I've updated the initial report to show this.
iamtalhaasghar commentedon Mar 13, 2026
Wasnt an issue at all but since few days (or weeks) it started happening with me as well.
Version: 16.1
Edit: Dont optimize background usage is already on for K9 on my phone.
PythooonUser commentedon Apr 27, 2026
Same here. EMail sync has never worked for me. I always have to open the app and manually sync to get new emails. No notifications either.
2 remaining items
seniordevel commentedon Apr 28, 2026
Same issue here with android 15 and moto g15, background usage allowed, battery optimization off. Using two outlook accounts.
No automatic polling/sync and no notifications.
Storage is not the problem here.
coreycb commentedon May 1, 2026
Marking as confirmed as this affects several users
seniordevel commentedon May 13, 2026
From my observations, this issue seems to happen when new emails arrive while Thunderbird is in DND (Do Not Disturb) mode.
I would expect DND to suppress notifications only, but email polling/synchronization should still continue in the background so that new messages appear in Thunderbird.
Instead, emails that arrive during DND are never synchronized. Even after DND is turned off again, Thunderbird does not poll those messages anymore.
Only a manual synchronization/polling action finally transfers those emails to Thunderbird.
cremor commentedon May 13, 2026
@seniordevel What you are describing sounds like a different issue. I've never used DND mode.
seniordevel commentedon May 13, 2026
@cremor Thanks for the clarification. You're probably right — this may actually be a different issue related specifically to DND mode.
I'll open a separate issue with detailed reproduction steps, since the behavior seems reproducible on my side.
M00T1CU5 commentedon Sep 27, 2026
Adding my name to this list of affected users, as i've just recently started using Thunderbird on Android with the new 'Thundermail' mailbox. Having this exact issue with the background sync; it never syncs, despite it set at every 15 minutes and my inbox has 'Enable sync' toggled on. DND is not turned on, background sync for Thunderbird is enabled (default of 'Optimised').
Android: 17
Phone: Google Pixel 10 Pro XL
Thunderbird: v23.1
M00T1CU5 commentedon Sep 28, 2026
I have actually found a solution that worked for me with this. With Push disabled after making the change below, i get the email notifications and the background syncing working close to within the 15 minute window.
I suspect the long-term solution to this would be for Thunderbird to prompt permission for this setting during first launch/setup, and setting/notice in the settings to check if it's disabled?
On my Google Pixel, I went into:
cremor commentedon Sep 28, 2026
@M00T1CU5 Thanks for the suggestion! But could you please explain the required setting a bit better? I can't find it in my Pixel 7a with Android 17.
When I go to settings - apps - Thunderbird then I can't find any "alarms and reminders" or "advanced" there. In the "permissions" sub menu is also no "alarms and reminders" (only notifications, contacts, nearby devices and camera).
The only place where I found "alarms and reminders" is in settings - apps (not selecting Thunderbird here) - advanced - alarms and reminders. But this menu only shows a few apps to grant the permission and Thunderbird isn't one of them.
migltigl commentedon Oct 3, 2026
I found the solution to always and immidiately sync folders.
https://support.mozilla.org/de/kb/configure-push-email-thunderbird-android
For me it solved by enabling all settings regarding "inbox folder.
But now I have a permanent message sitting there with "waiting for messages"?
As soon as I delete this push message, it doesnt work again.
Kinda weird.....
cremor commentedon Oct 4, 2026
@migltigl Using push is an alternative to polling. But it is not a fix for this issue. Polling should still work if I want to use it.