I am getting this Salesforce Exception:
"FIELD_INTEGRITY_EXCEPTION, Opportunity/Account ID: id value of incorrect type: a4tS00000008dtBIAQ: [WhatId]"
while trying to create a Task on custom object using Apex code.
I am storing Object id in to ID field like
ID whatId = record.id; and setting it in Task object whatId field.
I am not able to add Task on custom object using object Tab. I am not getting any option to create task on that object.