Re: BYOD AT&T HTC One won't MMS

Try this, it works on mine:

1. Slide the Notifications panel open, and then tap .
2. Tap Mobile data> Access point names.
3. On the APNs screen, tap > New APN.
4. Enter the APN settings.
5. Tap > Save.
6. Select the new APN on the APNs screen.
7. Touch Access Point Names or APNs.
8. If there is a T-Mobile APN, touch it. If not, press the key, and touch New APN.
9. Enter the following settings for the Data APN:
   • Name: T-Mobile
   • APN: fast.t-mobile.com
   • Proxy:<Not set>
   • Port:<Not set>
   • Username:<Not set>
   • Password: <Not set>
   • Server:<Not set>
   • MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
   • MMS proxy:<Not set>
   • MMS port:<Not set>
   • MMS protocol: WAP 2.0
   • MCC: 310
   • MNC: 260
   • Authentication type:<Not set>
   • APN type:<Not Set> OR Internet+MMS (depending on software version)
10. Press the key.
11. Touch Save.
12. In the list of APNs, delete all others that may appear. If there is a FOTA APN, you may leave that one. To do this:
    1. Touch the APN you want to delete.
    2. Press the key.
    3. Touch Delete APN.
13. Verify that there is a circle next to the one remaining APN to show it is activated.
14. Reboot the device.
15. Test your data connection, by accessing a web page or sending a picture message (MMS) to yourself.