After lockout time exceeds it shows 401 unauthorised error

When an IP gets locked out by defender and the time of the lockout exceeds 300secs and I try to login I get a 401 unauthorised for the server and takes more than 1 hour for the login to be released. Can't be done manually and doesn't appear on the logs. I have tried multiple browsers. As soon as I switch to a different IP address (hotspoting to my mobile) the problem goes away.
We tried with websites I have that don't have defender and the problem doesn't occur. Also tried with another plugin and works well with that.