I am having similar issues with a T-Mobile branded LG G2 (D801) and an AT&T sim card. I cannot send any sms messages. The really strange thing about it is, that it worked before I traveled to Europe for two weeks at the end of December. Since I got back to the US, no more text messages (I can only receive them). Very frustrating.
I tried updating the SMSC number, but I get an update error when trying to set a PDU number. I can set a regular number but it won't help. When I click "Refresh" the value in the box is "+13123149810",145
Can anyone help?
Thanks