Certificate issues with Iphone

While I can access my nextcloud server from Linux, android and mac, when I try to connect with iphone I get:

The certificate for this server seems to have changed
Do you consider…

If I say yes , it goes away until I try do something else with nextcloud. It does not transfer any files.
I am running nextcloud 24.0.2 and ios 16.0.2

Does anyone have an idea?
Thanks, andi

I have the same issue.
Do you have a reverse proxy?

No I don’t.

It is a public SSL certificate, if you test your server, there are no major issues?

If you check the server access logs, for the ios client, is there a strange file requested just before or something rejected?

It thought about the server discovery, however this is rather for cardDAV/calDAV on mac devices (General troubleshooting — Nextcloud latest Administration Manual latest documentation).