Just installed latest Android from Google Play Store and wanted to synchro with my Nextcloud
I do enter the nextcloud url, login and pass, check synchro, ok
Go back to the menu, synchro is put again to Dropbox…
After pressing the “Check config” button you still need to press Save at the top of the screen to save your settings.
This is a known UX issue in Joplin - someone has suggested in another thread to auto-save after pressing that “Check config”, which we should probably implement.