OMV 3.0.77 no connection with Android Syncme/Foldersync

Hello,
with the help of this great forum i could solve every problem myself. But after updating from omv 2 to omv 3 i need your help.

I did a fresh install of OMV 3 on an HP Microserver Gen 8, 2 x 3 TB WD RED as singledisk.
I installed Nextcloud 12.0.0 with the help of the NextCloud Installation Guide, everything is working well, i am syncing the contacts from my android phone and davdroid with nextcloud, also syncing files with my win 10 notebook and nextcloud using the nextcloud windows software is working.

But, i additionally want to sync photos between my android smartphone and nextcloud using the apps foldersync or syncme.
With both apps, it is not possible connecting to the server. The app says: Could not read folder contents, login failure, check username and password.

I use the same login settings as on my windows notebook and the nextcloud software.

Can you please help me solving this problem? Before i ran omv 2 with owncloud and have had no problems.

Thanks in advance

Philipp

Thank you for your answer.
Both try to connect to network shares on the server. That worked with OMV 2, with OMV 3 not. Maybe its a problem with both apps, cause with every client, linux or windows notebook i can connect.
The nextcloud android app is what iam using now, didn't know that i can sync folders.
But its working fine.