It is an upgraded site that runs now on EE 5.2.0 without major troubles.
Only when I save channel settings in the CP there is always this error message. Data is saved but this is the message:
SQLSTATE: Integrity constraint violation: 1048 Column 'default_author' cannot be null: UPDATE `exp_channel_form_settings` SET `default_author` = NULL WHERE `channel_form_settings_id` = '1'
What do I need to do to get rid of it?