Jitsi mobile app is not working on my android phone, on others it does

Hello, I have my own jitsi server running. It works good for a lot of different user (windows:firefox,chrome; linux:firefox,chrome and/or android/apple: mobile app).

On my wife’s android phone the “jitsi mee” app from 8x8, Inc Communicationis is working.
But not (anymore!) on my android phone :frowning:

with tcpdump on port 443 on the jitsi-server, I see the connections coming in.
in the nginx error.log I have the following error:
“2021/10/28 10:25:20 [error] 771#771: *8611 connect() failed (111: Connection refused) while connecting to upstream, client:, server:, upstream: “”, bytes from/to client:0/0, bytes from/to upstream:0/0”

One funny thing to know:
In the chrome browser on my android phone, jitsi works!

I think the problem is some were in the android app, things I tried…
I deinstalled the app.
I removed the data
I cleared the cache.
Phone restart’s
But nothing gives me a working jitsi meet app :frowning:

Does anyone of you out there have an idea ???
Is the fix on the app? or maybe still on the server?

Greetings Andre