Opposite for me.
I couldn't send 4 or 5 last night.
I rebooted the phone and all was fine....but it would send and then a few minutes later it would come back with a red X and say it was unable to send??
When my phone was brand brw I had a delay in sending. Called 611 and they refreshed a few things on their end. He sent me a test message and it was lightening quick. No pun intended