I am encountering a very strange problem. I worked with emacsclient for a while but suddenly, after starting an emacsclient frame the frame disappears shortly after start when interacting with it. It seems that the process keeps running but the frame is just gone.
The server is running, restarting it don't change anything. I am using
emacs now again, because it works fine. I also can start
emacsclient -t to run in terminal, which is also working fine. Just using
emacsclient -c stopped working as expected.
I also tried
emacsclient -e "(make-frame)". This worked once, now stopped working with error message
*ERROR*: Unknown terminal type.
I am using Ubuntu 18.04 with standard bash. Emacs is 27.0.50, built from source, GTK+ Version 3.22.30.
Maybe someone knows what I am doing wrong or can give me a hint how to debug this.