imessages don't work on mac
So, i used to be able to use messages on my mac but it stopped working a while ago and i haven't been able to use it. i have tried so many things and I realised today that it is because i only use my phone number for my imessages on my phone and not my apple id. I then tried to add my apple id but it didn't work and said - "an error occurred during activation". This is what also happened on my mac. My time zones are correct, my devices are up to date and i have no idea what to do. Please help! Thanks
MacBook Air 13", macOS 10.14