Hi @indramushoddaq,

This is 100% related to your website. In such a case solutions like creating Firewall rulls and allowing yourself via UFW unfortunately won’t work.

Having said that, I’ve went around digging a bit at the problem. Here are a few suggestions to try out

Plugin compatibility
*Briefly *disable all other plugins and enable the Twenty Nineteen default theme.

If this solves the problem, as it likely will, enable everything one by one, checking each time to see when the problem returns.

If you can’t disable all the plugins due to some reason, I see you’ve mentioned Wordfence however is it possible that you by any chance are using iThemes Security plugin as well? If you are please disable the following option -Filter long URL strings (under System Tweaks). The password error URL is really long because of the error code.

Hope this helps!

If this still doesn’t work, come back and well further dig around to see what’s going on.

Regards,
KDSys