My mac apple ID won't authentic properly with my Imessages

So I have a Mac Mini and I don't have phone access to use with my Mac Messages. And I looked online to see if anyone could help me and I tried the solutions other people were saying to do but it still wouldn't authenticate. And I have used my apple ID with messages on this account before but it stopped working suddenly. I just really want to get into touch with some friends. I can't authenticate it with my phone because I don't have my phone with me and so I really need some help with this situation. If anyone is able to help me please reply to this post. Thank you for your time.