Joshua Reynolds

Well I’ve since moved on to other similar plugins so don’t have it handy for an exact copy of the staging .htaccess file to make sure the top sections were unmodified but I’m certain about this section that was outright removed (except for possibly www at one point or other instead of staging):

<IfModule mod_expires.c>
ExpiresActive On
ExpiresByType image/jpg "access 1 year"
ExpiresByType image/jpeg "access 1 year"
ExpiresByType image/gif "access 1 year"
ExpiresByType image/png "access 1 year"
ExpiresByType text/css "access 1 month"
ExpiresByType text/html "access 1 month"
ExpiresByType application/pdf "access 1 month"
ExpiresByType text/x-javascript "access 1 month"
ExpiresByType application/x-shockwave-flash "access 1 month"
ExpiresByType image/x-icon "access 1 year"
ExpiresDefault "access 1 month"
</IfModule>
Options -Indexes

#### Manual additions by J_Rey
DefaultLanguage en

### Force HTTPS://WWW and remove trailing / from files ####
## Turn on rewrite engine
RewriteEngine on

# Remove trailing slash from non-filepath urls
RewriteCond %{REQUEST_URI} /(.+)/$
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^ https://staging.plcsource.com/%1 [R=301,L]

# Include trailing slash on directory 
RewriteCond %{REQUEST_URI} !(.+)/$
RewriteCond %{REQUEST_FILENAME} -d
RewriteRule ^(.+)$ https://staging.plcsource.com/$1/ [R=301,L]

# Force HTTPS and WWW 
RewriteCond %{HTTP_HOST} !^staging\.(.*)$ [OR,NC]
RewriteCond %{https} off  
RewriteRule ^(.*)$ https://staging.plcsource.com/$1 [R=301,L]

this was immediately after
# END WordPress

Its now obvious that another caching plugin didn’t cleanup after itself for the first part so was fine to remove that but with the last part that I (J_Rey) added missing then it caused 502 gateway errors till I added it back as shown above. There were other plugins installed but deactivated at the time (W3TC & possibly others) so wouldn’t change anything while testing your plugin although their section(s) were still there & your plugin added below them but above the WordPress markers.