I recently visited Taiwan for a 3 weeks and purchased a prepaid SIM on their network to use while I was there. Everything worked great. However, when I came back home to the US and put my Verizon SIM back in the phone, I no longer have mobile data working. I can make and receive calls without issue, and WiFi and Bluetooth are no problem.
I have reset the network multiple times and that did not work. All of the updates have been installed. I have powered down and removed the SIM card and put it back in and powered back up and no luck. Verizon 3G is showing up in the top left corner of my iPhone 6.
What should I do to get the data connection working?
Thanks for any assistance you can provide.
Your APN may be messed up. See if this KB offers up any assistance. View and edit your Access Point Name (APN) on your iPhone and iPad - Apple Support
You may need to either remove the Taiwan Carrier's settings out, or reset the APN all together.
An issue that Verizon do not know about, which applies to Vodafone UK users, and may apply to you, is that Vodafone downloads a Profile to the phone (can be found in the general part of settings). This profile is retained through every reset operation. Everything else does not work to restore date service - deleting the profile instantly does so.