MacBook Pro 15" macOS Catalina iMessage Activation Error
I am unable to activate iMessage. When I sign in using my Apple ID and PW, it gives an error: "Could not sign into iMessage. An error occurred during activation. Try again."
I have followed various instruction online, including restarting, turning iMessage off and on on my iPhone, reset my Apple ID PW, turned off keychain, and reset the RAM. I'm still getting the error message.
I'm connected to WiFi, and iMessage works on my iPhone 11 Pro Max.
MacBook Pro 15", macOS 10.15