Help with possible conflict

It’s not a theme issue at all, and it’s not a conflict. It’s a bug in the plugin.

The plugin is using http://accutonepiano.com/wp-content/plugins/simple-lightbox-gallery/lightbox/img/icons.svg for the background image URL on the button. That doesn’t exist (and probably wouldn’t work if it did exist). It looks like the correct URL is http://accutonepiano.com/wp-content/plugins/simple-lightbox-gallery/lightbox/img/icons.png

When I change the background-image URL in my browser debugger (on all three buttons), they look right.

OK. The svg file is actually present on all your sites.

You have an issue with the server configuration. The site that works (nysbs.org) is serving *.svg files with a “Content-Type: image/svg+xml” html header. The other domains are serving the *.svg file with a “Content-Type: text/xml” html header. Since you’re using the icons.svg file as a background image, the browser won’t use the file because the web server told it that icons.svg is a text/xml file, not a valid image.

What web hosting service are you using? Look for “MIME Types” on your control panel for the web hosting accounts, and configure those accounts to send *.svg (and *.svgz) files with a MIME type/Content-type of “image/svg+xml”

You can verify this from the command line with wget:

This is the one that works.

$ wget -O – -o /dev/null –save-headers http://nysbs.org/newsite/wp-content/plugins/simple-lightbox-gallery/lightbox/img/icons.svg
HTTP/1.1 200 OK
Date: Sat, 15 Aug 2015 18:42:01 GMT
Server: Apache
Last-Modified: Wed, 05 Aug 2015 16:32:17 GMT
Accept-Ranges: bytes
Content-Length: 1431
Keep-Alive: timeout=5, max=100
Connection: Keep-Alive
Content-Type: image/svg+xml

Here’s one with the problem:

$ wget -O – -o /dev/null –save-headers http://accutonepiano.com/wp-content/plugins/simple-lightbox-gallery/lightbox/img/icons.svg
HTTP/1.1 200 OK
Date: Sat, 15 Aug 2015 18:44:39 GMT
Server: Apache
Last-Modified: Sun, 02 Aug 2015 12:12:58 GMT
ETag: “7ae03c0-597-51c52f93d6680”
Accept-Ranges: bytes
Content-Length: 1431
Vary: Accept-Encoding,User-Agent
X-Powered-By: PleskLin
Keep-Alive: timeout=3, max=300
Connection: Keep-Alive
Content-Type: text/xml

Until that last line comes from the server with “Content-type: image/…”, that plugin won’t work (neither will anything else that uses *.svg files for background images).

Until then, if the developer can tell you where the ‘icons.svg’ text is, you could change it to ‘icons.png’ instead. I found the ‘icons.png’ file in the same directory as icons.svg on the accutonepiano.com site.

Who is your hosting company? What kind of control panel do you have for the hosting service?

Usually, you have the controls in your web hosting “control panel” to set this for your hosting account(s). For example, if your hosting service uses “cPanel” for the control panel, look for “MIME Types” on the main cPanel page.

You need the “MIME type” for files ending in ‘.svg’ and ‘.svgz’ to be set to “image/svg+xml”

If you need more info, you can email me, eric at mrmfl dot net.

Maybe this helps:

How to Add a Mime Type to a Domain in Plesk

Or check with tech support at your hosting service. Even the ‘live chat’ people can probably find the information for you.

UPDATE:

I found this page, which has better pictures to follow:
How to add new MIME type

Add two. For the first one, the extension is .svg and the application ‘image/svg+xml’. If that isn’t a choice, pick the “custom…” and enter ‘image/svg+xml’ there.

In case your plugin developer compresses his files, add the extension ‘.svgz’ with the same ‘image/svg+xml’ information.

Wow. I just realized that’s how the cPanel interface works, adding line(s) to “/public_html/.htaccess’.

This isn’t hard to do manually. Just put this line at the top of the .htaccess file in your site’s root directory.
AddType image/svg+xml svg svgz

Depending on your permalinks settings, there could be a WordPress section that start with a ‘# BEGIN WordPress’ line and ends with a ‘# END WordPress’ line. DO NOT put your AddType line in that section. WordPress will overwrite that section and wipe out your addition sometimes (for example if you change your permalink settings).

You can use FTP or your file management tools on your hosting service to update the .htaccess file, or you could use the WordPress .htaccess editor plugin.

Always make a backup of your .htaccess file using FTP or your hosting control panel before changing that file. A corrupt .htaccess file can make the directory unreachable through the web (it can cause “5xx” web server errors), so if you use the plugin to edit the file, you might not be able to get to the plugin to restore its backup file.

In case you’re interested. Apache documentation about the AddType Directive.