Relate custom module to task

I created a custom module. I want to relate tasks to that module. I created a one to many relation between task and the custom module. I added the custom module to the parent_type_display dropdown. On the task record, I can set the “Related To” field to the custom module, but when I try to search for a specific record from the custom module, I get “Error occurred while retrieving records” message on the screen, though no error exists in suitecrm.log.

I’m on version 8.7.1.

Any thoughts?