If you run multiple single-site WordPress installs in one hosting account, and your root .htaccess routes each domain to its own folder (for example):
RewriteEngine on
RewriteCond %{REQUEST_URI} !^/domain/
RewriteCond %{HTTP_HOST} ^domain.com$ [NC,OR]
RewriteCond %{HTTP_HOST} ^www.domain.com$
RewriteRule ^(.*)$ /domain/$1 [L]
Really Simple Security’s default HTTPS redirect can conflict with this setup and produce incorrect URLs such as:
https://www.domain.com/domain.com
To fix this, add domain-specific redirect rules to the root .htaccess; the file in the folder that contains all site folders. It probably looks something like this:
- root folder, with root .htaccess
- domain1
- domain2
Add this before Really Simple Security’s redirect rules:
RewriteCond %{HTTP_HOST} ^domain.com [NC]
RewriteRule ^(.*)$ https://www.domain.com/$1 [L,R=301]
Replace domain.com and www.domain.com with your actual domains. Repeat for each site in the account.