Newsletter Plugin blocked

I experienced some trotrouble with the well known plugin “The Newsletter Plugin”. Any subscription confirmation request is rejected as “bot”.
The confirmation is fone with a link in this format:
Mydomain.con?something=something

I tried to whitelist this parameter but it is still unstopable. Even switching off all features of cerber doesn’t help. The only solution is to disable cerber, which is not tge preferred solutn ..

Any idea?