Here:
  • APN: epc.tmobile.com
  • Proxy: not set
  • Port: not set
  • Username: none
  • Password:
  • Server: *
  • MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
  • MMS Proxy: 216.155.165.50
  • MMS port: 8080
  • MCC: 310
  • MNC:260
  • Authentication Type: Not set
  • APN Type: not set

Or try this one:
  • Name: T-Mobile US
  • APN: epc.tmobile.com
  • Proxy: (leave this blank)
  • Port: (leave this blank)
  • Username: (leave this blank)
  • Password: (leave this blank)
  • Server: (leave this blank)
  • MMSC: http://mms.msg.eng.t-mobile.com/mms/wapenc
  • MMS Proxy: (leave this blank)
  • MMS Port: (leave this blank)
  • MCC: 310
  • MNC: 260
  • APN Type: (leave this blank)

Or maybe this one:
  • Name: T-Mobile US
  • APN: epc.tmobile.com
  • Proxy: 216.155.165.050
  • Port: 8080
  • Username: (leave this blank)
  • Password: (leave this blank)
  • Server: (leave this blank)
  • MMSC: http://mms.msg.english.t-mobile.com/mms/wapenc
  • MMS Proxy: 261.155.165.050
  • MMS Port: 8080
  • MMS Protocol: WAP 2.0 (don't know if this is important)
  • MCC: 310
  • MNC: 260
  • APN Type: (leave this blank)