iMessage & SMS not working properly

• Turn off and restart iMessage and FaceTime (The sequence is very important)

1. Go to Settings > Messages and turn off iMessage.
2. Go to Settings > FaceTime and turn off FaceTime.
3. Restart your device.
4. Turn iMessage and FaceTime back on. (Watch the GIF below)

• Still not activated after a day?

1. It might take up to 24 hours to activate iMessage and FaceTime. If the issue continues after 24 hours, follow these steps:
2. Make sure that your device has the latest version of iOS.
3. If you're using an iPhone, contact your carrier to make sure that you can receive SMS messages.
4. Contact Apple Support.

If you get an error when trying to activate iMessage or FaceTime ...

I can report something odd going on with SMS as well. My mother has an older iPhone 7, but running iOS 13. She can no longer (as of early February 2020) send or receive SMS text messages as part of a group. Individual SMS messages seem to work.

On my phone (iPhone 11) it works fine, but on my iMac (running Catalina) SMS messages are a mess. Existing threads only show partial messages, or show very old portions of a message. Again, the same thread on my iPhone is fine. Tried logging out and back into iCloud with no improvement. Restarted my devices...no luck.

iMessage seems to be working fine.