Im on AT&T using Pulse. No issues today but could barely send any texts a few weeks ago. Then I couldnt send or receive any images or they were horrible quality. Friends on Verizon & T-Mo had similar issues on & off too. I Uninstalled & went back to An Oct. 2020 version (5.4.6.2814) which was a version before the Pulse Dev joined up with some company. So far it's still good. I'm wondering if they have server issues sometimes.
Pulse for me has been the best SMS app for sure. Using on 2 phones, a tablet, Macs & a windows pc.