Android app not connecting to my server

I have been install and config jitsi meet on my ubuntu 18.04 server and use free SSL for SSL certification and in-browser everything is good and I can use jit si meet on my server without any problem.but in the android app when I use my server after seconds it shows me couldn’t connect to the server and try again.
I test my SSL and it a valid SSL certification.
can u help me?