The comdirect bank uses several different bank codes. The error message "Bankleitzahl passt nicht zum Benutzer (9210)" (Bank code doesn't belong to user) indicates that the wrong comdirect bank code has been selected for the setup.

Please open the wallet of Outbank and make sure to select the comdirect login with the bank code you received from your bank. If you are not sure which bank code is the right one, simply enter your IBAN into the search field and Outbank will give you the appropriate comdirect login.