"The information you have entered is not valid" when trying to log in

Hey team, just wanted to communicate that I have been having an issue related my log-in, the following error message pops-up "The information you have entered is not valid", I have tried many steps and none are of utility, such as:

- Changing my password multiple times
- Allowing WOW in firewall
- Disabling Read-only mode
- Changing networks and doing DNS flushes
- Changing realmlist and deleting WTF "cache"
- Re-installing the WOW client

This error message happened since my internet went down, I don't have any other device I can play from, please help me fix this, I like to relax after work with this game, thank you very much for your attention mates