iMessage Error when signing into Apple ID

Ever since I received my MacBook Air in late 2016, I have never been able to use iMessage. I've had many issues in the past, I've deleted keychains, created new Apple ID's and many other things. Today, I originally had an issue where upon trying to send a message, it would say all my contacts weren't signed up to iMessage, even though they are. After changing the settings on my iPhone to send and receive from both my phone number and Apple ID, the issue became that I wasn't signed in. So after clicking sign in and trying to sign in many times, it says there is an error in authenticating my account. I spent good money on this MacBook and I didn't expect such a simple feature to cause such headaches. Please tell me if there are any other things I can do to fix this issue. Or should I just take it into an apple store?