I'm having a problem with my text messages not sending as well. At first I thought it was just my group messages. I always get a notification that there's a "background restriction. click to remove". The clicking always worked before. Now, all types of messaging will NOT send. This is quite frustrating. FIX ASAP please.
The "background restriction" is likely due to your cellular data being turned OFF, whether purposely, or by using a battery saver/app manager program.... MMS (group, picture, even a signature, etc) won't send over wifi, you must have the cellular data enabled.
I never had this issue till I installed a battery manager program; it turned off my 4G/cellular and did NOT turn it back on when I tried to send a pic message, I just got the message you got. I have since uninstalled; my Droid 4 seems to manage switching between 4G and wifi quite well without Juice Defender, and my battery life is acceptable. I was just trying to see if I could improve it.
But I digress - I think your issue can be solved by turning on your cellular data. What phone are you using?