For me it just worked "out of the box" on my phone and tablet. My config : Account Settings Username & Password (same format that when you log in your server website, for me it is just the username, not username@domain.org) Server URL : https://webcloud.zaclys.com Sync on mobile data checked (but it also works unchecked) Sync frequency : 60 minutes (what you want but don't choose "No sync" !) Sync Folders Local Folder : /home/phablet/Documents Remote Folder : /Documents Local Folder : /home/phablet/Pictures/com.ubuntu.camera Remote Folder : /Photos/Aquaris Local Folder : /home/phablet/Videos/com.ubuntu.camera Remote Folder : /Videos/Aquaris Sync service you have to activate the service you can manually sync to test your config I use a server from Zaclys : https://www.zaclys.com/ They use the 8.0.4 Owncloud version but they offer the Nextcloud 12 version too. I tried too with Unixcorn : https://unixcorn.org/ with https://cloud.unixcorn.org and a 12.0.2 Nextcloud version but it never worked for me (no sync). I suppose that Owncloud-Sync doesn't works with Nextcloud. It would be great thought ! I hope all of this could help you.