MaxDB Studio - SQL sessions are not possible !!!

Dear Experts,

I need to import a few objects in a freshly installed MaxDB database 7.9 SP08 patch 40.
When I select the corresponding menu in Database Studio (Right click on the database -> Export / Import -> Import),
it gives me the following error:

Import is only possible with a valid SQL Login

I somehow painfully discovered, that the user CONTROL is meant only to perform DBA tasks, but has no rights
to mess with the data.

I killed the next 3-4 hours to figure out how to create a SQL user. Finally I managed to do this via sqlcli and I have
created a DBADMIN user. This user is legible and I can login with it via sqlcli and do stuff like select * from tables.

Nevertheless, when I try to login with this user in the SQL Editor in Database Studio, it keeps saying:

SQL sessions are not possible

or

Could not connect SQL due to: [-4008]: Unknown user name/password combination

PLEASE kindly help! This literally killed my whole day :-( I am not able to proceed further :-(