Here's the story. I'm on AT&t. Got my Nexus 5 last week, put my sim card from my LGOG into it. Everything worked beautifully (including MMS) and I was crying tears of joy.
Root it. Installed gravity box, noticed I had ten million quick settings tiles. Become giddy and click happy. Clicked one that toggled data type (LTE/2G/3G). MMS broke. Can't figure it out. Stopped clicking things. Uninstalled gravity box.
Change every APN setting after reading countless forums. Does absolutely nothing. Decide to wipe and install Cyanogen 11. Upon reboot after fresh install, 1 pending picture message got sent. Couldn't send anymore even after rebooting again.
Messed with all the apn's I saw fit, still nothing. Go to AT&T, completely useless but added my IMEI to the account. Got 1 picture to send upon rebooting again, then all the others failed just like before. Not sure what to do, occasionally crying tears of not joy.
Any ideas where to start to diagnose this?