Ok, then I think it’s clear that you will not reach my nextcloud - seems to be the same problem I had at the university as long my PC there was configured to use IPv4 only.

No, with a browser I can reach the cloud and use it; I also can use the Nextcloud sync client which is able to connect over IPv6 with my cloud.
As far as I see it is only Joplin sync which refuses to use the IPv6 address - in the error message Joplin states not to be able to reach the cloud over the IPv4 (!) address.

I’m going to open a GitHub issue … we’re gonna see what happens :slight_smile:

Thanks for your help !

Wolfgang