Have you updated world of warcraft with the two mini patches? And are you using the latest version of honorbuddy?
If when you purchased Honorbuddy it sent you a Key to your email, make sure you are putting that correctly into the HB Username, leaving the password blank. If you use an actual username and password to log in, go to: shop.buddymaster.com --There you can reset your password. Try to log into that site first with the username and password you used to log into HB
When I purchased it awhile back I was never given a key, I was given a bunch of confirmations though I can log into the buddyauth site just fine also. & Yes i have both patches mini patches. and the most recent build of HB
Okay. I want you to go to the downloads page (link at the top of this page) and click on Honorbuddy Releases, and click the latest. Download that .zip file. Unzip it into a NEW folder, don't unzip it over your old one. Doing so can cause many many issues. Also, were you able to log into shop.buddymaster.com ?