EteSync stops synchronising after a day or so [EteSync 2.4.3 | OnePlus 8 Pro Android 13]

[z-master42]

Hello, it's me again (#241 , #246).
Once again I have a problem with synchronisation.
I have now noticed that synchronisation works after a restart and then stops again quite quickly.
When it works, I see the typical blue "loading bar" moving under the Contacts, Calendar and Tasks entries and the entries under these categories are greyed out accordingly.
This is also how it should be when I start a synchronisation manually and this usually works after a restart. After a short time (e.g. the next day), the loading bars no longer appear when a synchronisation is started manually, only a pop-up appears at the bottom of the screen stating that a synchronisation has been started. But then nothing else happens. And when I switch on debugging, the log is also empty.
Maybe it's a problem in my Android and not the app.