T-Mobile Internet and MMS APN Settings for BlackBerry Classic

On the homescreen, swipe down from the top.

Tap Settings, and then tap Network Connections.
Tap Mobile Network.
Tap APN at the bottom of the screen.

Enter the following information:

Access Point Name (APN) = fast.t-mobile.com
Username =
Password =

Tap Save. 

Slide your finger left on the display to open the main menu.

Open Text Messages.
Press the dots.
Press Settings and select Text Messages.
Select MMS.

Press Advanced and enter the following details.

APN = fast.t-mobile.com
MMSC URL = http://mms.msg.eng.t-mobile.com/mms/wapenc
Proxy URL = :

Press Save.