T-Mobile and AT&T

Sounds like the two of you need to go through your blocked number list and unblock each other

We understand the importance of being able to receive calls from other carriers, Hannahkjames7.

What's the make and model of your device? Sharing this will allow us to come up with a more personalized solution for you. 

In the meantime, here are a few things we recommend trying to help resolve your experience:

• Turn your phone off, and then turn it on.
• Turn off Airplane Mode.
• Turn off Do Not Disturb or Quiet Hours.
• Turn off Call Forwarding.
• Check the blocked calls or reject list.
• Update device software.
• Remove and reinsert the SIM card if the phone displays Insert SIM or Emergency Calls only.

You can also sign in on our support page for step-by-step troubleshooting help. 

Let us know if this helps! Thank you for posting on the AT&T Community Forums!

Whitley, AT&T Community Specialist

I’ve tried all of that and nothing works I also try to call the number off a different device that has att and they don’t receive it

Hello @Hannahkjames7, we are here to help you with your phone calls.

Let’s meet in a Direct Message to discuss your phone calls. Please check your Direct Message Inbox (it’s the chat icon next to the bell icon in the upper right corner of the Forums).

We look forward to speaking with you!

Mellira, AT&T Community Specialist

I haven’t received a message yet

I had similar issue last year. AT&T whitelisted phones it decided to have on it's network. My phone had all necessary bands and supported voLTE but wasn't included in the AT&T list of allowed phones. I could use it for text messages and data but it didn't worked for voice calls. I had to get another phone. Try another phone that's whitelisted by AT&T. 

@tim9

The OP and his friend are able to make and receive calls... Just not to each other...

Not the same