Hello. Can you please make a screenshot of the 521 message?
Is it from Cloudflare?
The bot should login immediately after you press "login".
Also please remember that the username & password is case-sensitive (the same data you registered with at wolfbot.org). If you want to change your password, you can do it there too.
It worked for a second, however when I tried to update the configuration and reset, the modal window came up and it seemed to be hung for a while, so I left it for some time and it hadn't finished restarting. I closed the window and tried to re-open it, now it gives the 521 error.
The error is fixed. The bot couldn't perform the restart you requested "Back-Blade" in "Lending" mode (since that is a Trading config). I updated the bot so that it will always restart with default config if the settings are incorrect/not available.