Exception during GRANT CONNECT ON ENDPOINT to group managed service account

Question

Did somebody happen to make a GRANT CONNECT ON ENDPOINT:: operation to a group managed service account work? Personally, I can't.

I am always facing the so-called self-explaining exception:

Msg 15151, Level 16, State 1, Line 1 Cannot find the login 'DOMAIN\GMSA-ACCOUNT', because it does not exist or you do not have permission.

1. the login I use to issue this command is sysadmin-role, so permission shall not be a problem
2. the DOMAIN\GMSA-ACCOUNT account is actually starting the SQL Server engine service, so I guess its existence has been at least validated

As a consequence, I can't make my service broker communication work with gMSA account like it previously was, with a regular service account.

Does somebody have an answer/tip?

Thanks in advance.