Contact names not showing up in chat

[Revelation1714]

First, I want to say thank you for all your work and making this work! The app works great. but I have two issues...

1. Contact names are not showing up in chat. It only shows their phone number.
2. I cannot attach photos. When I click the paper clip to attach, it does nothing.

It sees my contacts when I type start typing in the "to" box.
But after I select the contact, it only lists their number. and my conversation threads have the phone number beside them, instead of the name.
I am using Windows 1909 build on Lumia 950.

After using it more, I also realized some messages were not sending unless I put a 1 (the country code) at the beginning of the phone number.
But some messages went through fine without the country code.
(I assume this is a carrier thing??)

[yuezhenglingluan]

Having the same issue with the chat app that I build from the latest source code using vs myself