Guests showing with different email/ Invalid email address from teams

Question

Hello

Please i need your help on this issue.

I want to know why the users UPN changes when I create guests. I have also created contacts. 

A member tried to send a meeting with Teams but stated invalid email address.

I added the contacts and then I also sent them an invite from Microsoft Entra but I noticed the UPN kept adding an "ext@netorg" the email would still show as is but in teams the guests will show as the "_ext " instead of there email. 

We are cloud only so it was done from admin portal.

I am not sure if it was synchronized.

I have cleared teams cache but did not work when I attempted it. 

It Seems like it adds the guest but does not recognize the guests contact email address.

I have tried both on Teams web app and app itself but the same issue.

The guests and contacts were created on admin portal.

It seems like guests and contacts do not seem to match up in Microsoft Teams

Guests do not have any necessary permissions when wanting to join but are not able to from what it seems like when sending an invite from teams.