Go to Case object and check under fields and relationships,if you have the Case_Department__c field and remove it as required field.
If this does not help you,create new trailhead playground and work over there just to avoid the conflicts which occured due to some pre exixting configuration.
As per the error, its seems like you are missing required field value at the time of DML(inserting record). And the field name is Case_Department__c
Regards,
Ganesh Hembram
I figured that out but there is no required field with that name as far as I can see! Thanks anyway
Go to Case object and check under fields and relationships,if you have the Case_Department__c field and remove it as required field.
If this does not help you,create new trailhead playground and work over there just to avoid the conflicts which occured due to some pre exixting configuration.
Best Regards,
Sandhya
It is so weird.
Thanks anyway