I test with issue with two key fields and I get the message which says that “A valid primary key must contain only one field for custom entities”. With only one key field, it can be saved successfully. It seems that compound keys are not supported yet. I would try to confirm if there is an official document clarifying this issue.
Best regards, Mabel Mao
Community Support Team _ Mabel Mao If this post helps, then please consider Accept it as the solution to help the other members find it more quickly.