You can help, no dayparts appear when updating. In sheduler in de form no daypart appears, it is empty
I suspect you have deleted the first super admin level user in the system and now the dayparts are owned by a user that no longer exists.
You’ll need to run some SQL on the database to resolve that.
UPDATE `daypart` SET userId = (SELECT userId FROM `user` WHERE usertypeid = 1 LIMIT 1) WHERE userId NOT IN (SELECT userId FROM `user`);
UPDATE `display` SET userId = (SELECT userId FROM `user` WHERE usertypeid = 1 LIMIT 1) WHERE userId NOT IN (SELECT userId FROM `user`);
If you need guidance on running SQL commands, there’s a document here which explains for a Docker-based installation: