Unable to logging ingame after following bug solution

Hello, I was following the instructions of the season-journey-and-achievement-bug-solution and after that, the game gave me the error Code: 1021 when logging in inside the game. I know the code is for “connection issues” and I followed all the instructions and nothing was fixed. Everything else in my pc is working perfectly.
If I am required to clean install battle.net and/or diablo 3, please explain how to. Thanks.

This is a support response to 1021 on another thread:

Also, if you have changed any network settings, such as firewall, DNS. Please review the changes. Wrong network settings may cause problems.

[Next day] interestingly enough, everything fixed it self without doing anything. Still, thank you for the reply.