I have configured an account for testing, which is also correctly entered in the fetchmailrc. The wrong line in the fetchmailrc is the line "set no fetchall". If I remove this line, the fetchmail service runs correctly until the time when the fetchmailrc is rewritten, then the error occurs.
Where can I customize what "grommunio-admin fetchmail write rc" writes to the fetchmailrc file (the Global settings part)?