Thanks for posting in the Community! Happy New Year!
Take a deep breath, I'm sure we can solve this. First of all, try emptying your cache. If you need any help with that, just tel me your browser and I'll post the steps. If that doesn't work, try logging in on a different browser or a different device. (Your phone for example.)
Tell me if this works, and don't worry if it doesn't, we'll just continue troubleshooting.
Okay, can you descibe exactly what went wrong? I assume you emptied your cache and got the same error, then tried logging in on another device and still got the error, right? Please tell me the exac error message.
Here's a couple other things we should try:
Do you have an email adress for Spotify? Please check it, see if you have a message from Spotify.
If your sure your username is correct, request a new password.