Mattermost Android app not connecting

Hello Guys,
Im new to mattermost and got a problem.

I installed mattermost on a Debian system and set it to listen on 443 and redirect to an https connection.

In our firewall Ive set that all request on the port 8065 should redirect to this Linux server on port 443.

So when I open https://ip:8065 in my browser then I can log in and use mattermost but when I try to connect the app to our mattermost server it says that it could not connect. Do I have to open another port?

I opened 8065 TCP for external to Linux server 443 internal.

Maybe someone can help me

Greetings from germany!

Hi @NexADR, please take a look at our troubleshooting doc as a first step: