SMS group text messages won't go through on MAC

I am running Sequoia 15.1 on my Mac. My cell phone is on AT&T and is running 17.6.1 IOS. There are Android and Apple phones in the group. I recently traveled to a different time zone. I can reply on my Iphone but I can't repy or start a text in this group on the Mac Air. I have shut down and rebooted both the computer and the cell phone. Any suggestions?