"An error occurred during activation. Try again."

I know that a lot of people have been having the problem of registering your MacBook for iMessage and getting the dreaded "An error occurred during activation. Try again." But I just thought I should ask the question again and see if anything comes up. I bought my mac in 2015 and it was functioning with iMessage for a good 2 years, it stopped about 4 months ago. There was an old forum for this in 2012 and someone suggested maybe getting banned from iMessage? I think that's unlikely, but I just want to find an answer and see if anyone else is having the same problem.