Sorry, for the ambiguous explanation.
The whole story:
2 weeks ago, i had insert a "predefined host" (= nas) on all android devices (without the minix)!
After that, the synchronisation (with advanced folders) was stable, but only for some days.
After some more tests, i decided to delete and reinstall all resilio instances, also the one at the nas!
In that case the installation at the nas generates a different listening port, to the first installation.
But i don't realized this detail.
So i configure all android devices again, including predefinde host with the "wrong" listening port.
So the connection was ok, but after 1 day also no more syncs again.
At this point i started this thread here.
Meanwhile i have found the issue and after correcting the android devices, except the minix, all synchronizes well!
Yesterday i started again on the minix to connect a standard folder. I wrote down a read only key, inserts it to the corresponding setting!
But no connection to the nas.
At the left bottom appears a message "transfer via mobile data network disabled".
Next thing is to take a look at the logs on the minix...
Or first, i try a connection over wifi! The minix, at the moment, is connected via lan cable!
(android via lan cable = something special!?!)
I'll report it shortly!