Agenda syncs only when connected in Wifi

I’ve checked everything several times. Syncing agenda from my phone to ecloud works only when the phone is connected in wifi.
I have a S9 refurbished with e 8.1.
In Paramaters>Accounts> xxx
Syncing data is activated.
In both accounts parameters, syncing in wifi only is disactivated.
In accounts>syncing , only syncing data and videos is deactivated
In Parameters>Network>Data conumption>Data saver is deactivated (once was activated but nothing changed)
When I’m not connected in wifi, even if I order a manual agenda sync, nothing happens if I’m not in Wifi.
If I connect in Wifi, it works immediately.

Is it a bug or did I misuse something ?

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