Every text message I have sent today has failed. Galaxy S4 worked perfectly until this morning. Restarted the phone and had one succesful outgoing text then all the rest failed. Took battery out, removed sim card.....still failing.
Follow this Link and Video on Youtube it's all I find so far.. you might try Google Searching cache Wipe Galaxy S4
http://www.youtube.com/watch?v=vUBt-MW_RtE
Try a clearing of the Cache Partition or you might try a Factory Reset..
How do I do that?