add_role menu pages are not visible

The problem was, that I changed the capabilities AFTER I already created the role. I noticed, that if I change the roles slug, the role became duplicated. So I searched, and found

remove_role( 'tabellenadmin' );

Add that line somewhere before add_role(). You first have to remove the role, before you can change it.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)