In subject lookup, some subject items are not showing Dynamic 365 CRM

 I faced a scenario where some subject items are not showing in subject lookup.

We are using Subject lookup on the Case form and creating cases for different subjects.

We have added a new subject in the subject entity but it's not showing in the subject lookup.

The issue is coming because there is an OOB field in the subject entity with a name featuremask and its value is null.

So I have updated its value to 1 then it's showing. by the following query.

update subject set featuremask = 1 where subjectid = "Provide your subject id here"