Wednesday, January 25, 2017

HTC 10 Won't Connect to T-Mobile International Data Roaming

I bought an unlocked HTC 10 through a 3rd party vendor and have enjoyed the phone. I use T-Mobile service because of their great value and their free 2G international data roaming. Unfortunately, I ran into trouble connecting to cellular data the first time I traveled outside the USA with my new phone.

After arriving in Hong Kong, I received the helpful T-Mobile text message telling me I had data roaming available:

"Welcome to Hong Kong! Your T-Mobile plan gives you unlimited data at 2G speeds, calls at 20 cents/min and free texts."

Text messages and phone calls were working, but cellular data refused to connect.

Troubleshooting steps I tried:
  • Confirmed data roaming is on
  • Put phone in airplane mode for 1 minute
  • Restarted phone
  • Tried manually connecting to every carrier. Only the automatically selected one worked
  • Enabled roaming via USSD code: #766#
  • Tried manually specifying each network type (2G, 2G/3G, 2G/3G/4G)
  • Tried my T-Mobile SIM in a different phone (worked)
  • Tried a local SIM from the roaming carrier (Hutchinson 3) in my phone (worked)
  • Tried a different T-Mobile SIM, that I know works, in my phone (didn't work)
  • Asked T-Mobile if there was any block on my number for international roaming (nope)
Much of this was suggested by the very helpful T-Mobile support team and though we whittled down the problem to something specific with my phone, they never determined the exact issue. Finally, HTC customer support suggested I check my APN settings. Sure enough, they were different between my 2nd working phone and my HTC 10.

There's a known issue with the LG G3 phone not having and not automatically downloading the correct APN settings to allow T-Mobile international roaming to work. Apparently, this is also true with my HTC 10 phone, though no amount of Googling mentions it.

I believe the HTC 10 is supposed to read its APN settings from the SIM card, but instead, when a new SIM card is inserted, it prompts the user for the carrier associated with this SIM. From this user selection it populates the APNs. It appears, this hard coded list is outdated, even after an update to Android 7.0.

With the problem finally understood, several sites mention how to manually enter an APN which enables roaming. The steps are:
  1. Open Settings > Mobile Data > Access point names
  2. Copy down the settings of the currently selected Access Point
  3. Create a new Access Point with:
    1. Name = RoamingAPN
      • This can be any name
    2. APN =
    3. APN protocol = IPv4
    4. All other settings the same as the currently selected APN
  4. Save (with the triple dot menu)
  5. Select the new "RoamingAPN"
My HTC 10 connected within 15 seconds and displayed the H icon in the notification tray.  Though, you may need to reboot after making this change.

This worked for me and hopefully will help other HTC 10 owners.



  1. I cannot thank you enough for this. Got into Canada yesterday and even after a long call with T-Mobile, my HTC would not connect to Telus here. Your APN entry fixed the whole thing. Cheers!

  2. Its valuable and nice information about International sim .Thanks for such a nice post, please keep sharing such post in future .