Hi, I have the same problem, in my case when the issue happend I checked the .htaccess file and the last modified date of the file was changed, editing the file I found that the code for WPS Hide Login dissapear, I mannualy included again this code at the end of .htaccess file and the problem was solved but i do not know why or what changed the .htacess file, I had this problem in two websites and in both I ahve seen the same issue.
# Hide Login
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ – [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
#END Hide Login
