your test gave me the clou.
Created a new account, log messages looked good and mapping to home directory possible.
My guess is that since I created the home directories with rsync data transfer from old server that after changing the GID/UID this wasn't sufficient and probably causing the connection error.
The UID as well as the GID are wrong, because they are the unix parameters of the old server, not the samba parameters.
How easy the solution can be.
Thanks for all support helping me to the solution.