I upgraded to a new iMac running Catalina. Since doing this, I’m having trouble sending messages to my daughter and maybe others. At first she did not receive any messages from me, but others did. I solved the problem using a solution from Ask Different. I thought the problem was solved. But now I found out that about a third of my messages are not delivered to my daughter. We text several times a week, and before my new iMac everything went well. I write from iMac, iphone and iPad and previously all three worked well. Now they do not. It may be my daughters, but it’s just me. and in the same way, as far as I know, it only happens when I send to her. She does not receive everything. Has anyone else had this problem, or does anyone know what could be causing it?