Forward from email to many recipients

we use a email address. We want to forward mails to several recipients. When we enter a second one in the forward section, we get an error.
We tried both with comma (as stated in the help) and without as done in another account some time ago, but with the same error.
Could you please help us?

ok we just found out what to do and what the problem/effect is:
you have to enter the email-addresses with ONLY a comma but without space or linebreak.
That works. But if afterwards you look at your forwarding addresses again, they are listed WITHOUT comma and WITH linebreak. If you then do any changes there without adapting the format again to “comma and nothing else”, you will get the error…