I have an iPhone, iPad and a Macbook. All are interconnected for iMessage and I can use my Macbook for SMS texting as well via forwarding. Lately, my SMS texts, only, are not going through and I get a red exclamation point and an undeliverable message. This tends to occur when I send a longer message. One liners go through not problem. The line on top that shows the progression of the message being sent will move rapidly toward the end, then just hangs. It will do this for a minute until it says undeliverable. If I hit retry, sometimes it will go through, others not. If I send the message to myself on email it goes through fine, but not to another person's non-iPhone.
I reset my router incase that was the problem. I turned off messaging and turned it back on. I turned off forwarding (still happened on just phone) and turned it back on. Same thing. Both devices.
I just posted another question about mail hanging too, and it seems both problems started around the same time.
Any suggestions would be most appreciated!