m2o in background from script not running

[spinne1000]

I am running m2o under Debian11 like from command prompt in a bash terminal:
m2o -v m2oMidi -o 7700

works fine.

If I run it it background like:
m2o -v m2oMidi -o 7700 &
it also works.

But if I do the same from within a script:

#!/bin/bash
m2o -v m2oMidi -o 7700 &

while true
do
    #some more stuff until ctrl-c
    # want to start a midi note generator here and then aconnect it to m2o (or disconnect)
done

in another terminal:
ps -elf does not show the m2o task. I tried it with nohup in front of the line with the same result. The same with disown at the end of the line.

Any ideas how I can run m2o in background from the script?

thanks