Remote Access from another PC

Hello

I'm trying to have another Teamviewer ID, connect to a particular PC.

I used to be able to use the other computers ID, and setup a specific password, and everything would work.

This no longer works....why?

I will not have the other user, create a Teamviewer account, and then use that. This is ridiculous.

Why can't I use just the teamviewer ID, am I doing something wrong.

Blacklisting, White listing, is no help either

Again, I will not use another Teamviewer acct., just for a simple connection. 

Regards