Did you (or someone who’s familiar with locking down wordpress) setup a redirect on the wp-admin by via .htaccess or some other way from end users being able to access the wp-admin ?
There are some methods that do that, but make it so that if you login via that login stuff you have on your home page *Then* go to your /wp-admin it will work.
Unless you are logging in via your home page and its redirecting you to 404 there, that probably means whatever redirect plugin or change to the .htaccess is not working properly and we would need to have you ftp into your site and check those .htaccess rules to see if it’s that and give us a list of plugins that you are running that could possibly do that by viewing teh wp-content/plugins directory via ftp
Its all fine now 🙂
It was just because of login plugin which I deactivated and then actived again and now its working fine.
Thank you for your help Frumph.