Related module not populating the information

Hi I am working for a client, and I have created two modules, module one is used for storing human attributes like name, contact details, preferences etc. Module2 is a service, that I create and would like to relate to module1.

I have created a one to many relationship for module1 against module 2.

In module 2 I can see the text field customer name, it is a drop down that allows me to search for a user.
But when I search for the user, it does not show any user even though I have created a few for testing.

Besides the customer field, I can see an arrow, when I click on it, I get a window displaying the users I have created. But it does not let me select it.

Could someone please guide me what it is I am doing wrong?

Thank you in advance

You can share screenshots here.

Also, check if you have errors in the log files.

Image 01 - The empty fields of module01 that collects user details.
Image02 - after the users are created, list view of users. these user’s are not clickable, like the users created in account modules.
Image03 - Second module which has a relationship with first module, when I try to select the user, it does not let me.

I am sorry if this is a basic issue, I have been reading and testing, but unable to get this to work.

Have you been doing Quick Repair and Rebuilds after changes done in Studio?

And also try a Repair Relationships

Yes I have made it a process, everytime I deploy something new, I do a quick repair, I also have done repair relationships.

I have even tried installing it on a dedicated server, unfortunately, I could not get it to work, but still trying to do this and documenting it, so I can share it once it works successfully.

Nowadays, I am trying to play around with the code it self - but even that is not working.