Unable to search Customer Using Unique Field

Hi there,
I have created a user id field in customer doctype.
and also set the search field for it.
But unable to search it based on that.
Also tried to create another field and tested.
What wrong might I be doing?

Adding Some Pictures for the reference.

This may require some custom scripting. Hope you will find the below post useful.

Thanks for the support
I’ll try and revert back here for difficulties.