Unable to use Ctrl+A+D to exit screen session of Termius

I am using Termius Android app on my phone to SSH connect my server. When I get in a screen session, it can't input Ctrl+A+D to leave this session, only Ctrl + one key can be input. Also, my program in this session keeps running, so I can’t run any command unless using Ctrl+C to stop my program, but that is so stupid for just leaving a session！ Does anyone meet the same problem as me? It's much appreciated if anyone knows a solution. Expected result: Realize the Ctrl+A+D effect in normal