I have a Wordpress site that I wasnt using SSL with, then added SSL with Lets Encrypt, all done via the Virtualmin backend. I can now no longer access the Wp-Admin backend of my site, but I can access the rest of the pages. I get a 404 when I try to access wp-admin.
I also recommend these days to ensure that you install Wordfence Security. I moved away from this plugin in the past but now it has evolved I think into one of the best security plugins for WordPress https://wordpress.org/plugins/wordfence/
So I found out what the problem was. I had installed the WPS Hide Login plugin before I enabled SSL. The plugin was changing changing my wp-admin to http://url.com/login
So, I deleted the plugin via FTP then just re-installed it and it works.
ftp insecure? that sounds just like google excuses for removing ftp support from chrome.
people have the option of ftps, sftp and scp… much better (security-wise) than a production server file manager run in a browser…