Hi moi

Can you confirm you've allowed the app to run in the background and excluded it from any battery optimisation in Android's power management settings?

Closing Thunderbird using Android's background app manager can also stop the sync process.

I have already opened the app in Parameters / Application / Thunderbird in Battery section, I have set "no restriction" to use the of battery in background

there is not specific menu to enable a app in background

in app menu, as recommanded by gemini.google , there is a sub menu to enable alerts but i dont see thunderbird in the list

I have already set "no restriction" to use battery in background for Thinderbird in app menu but not working

Are emails being successfully received and sent when you manually sync the account?

Have you verified a new email is waiting for download on the server prior to sync.

POP3 accounts typically delete emails once downloaded by another email client, unless the behavior is changed on the server. Pop3 was only ever designed as a single client protocol, unlike Imap.

yes email are received and send when I sync manually on my Android phone

I have configured Android Thunderbird not to delete the messages on the server I only delete the messages on the server when I read them from my personnel computer.

I think the problem is : "Thunderbird is not running in background on my phone" although I have set "no restriction" in Battery menu

Gemini.Google IA says to enable Alerts on Parameters/Applications/Special Access but Thunderbird is not in the list of eligible applications