One of the strengths of WordPress is the tens of thousands of plugins available (for free via the WordPress.org plugin repository and for purchase). However it can be an Achilles’ heel at times.
When you start mixing 10, 20, or 30+ plugins written by different authors and never tested against each other, sometimes issues arise. To the site owner, it looks like the latest plugin “broke their site” or “it’s not working!” That may be the case, but it’s often more complicated than that.
Poor coding practices in some plugins can break or affect other plugins — which is why it’s important to follow a troubleshooting plan to isolate the issue so it can be solved quickly.
Step 1: Read the FAQ
It’s possible (even likely) this is a common problem for which a solution already exists. If you don’t read the FAQ first, you frustrate the plugin author by asking for an answer that already exists … and you delay fixing the issue.
Step 2: Search the plugin support forum
Even if it’s not in the FAQ, a quick search in the plugin support forum may turn up others who have had the same issue and found a fix.
Note: The same symptoms don’t always mean the same issue, so be careful assuming (and piling onto) an existing thread.
Step 3: Isolate the issue
3a. Check for plugin conflicts (most common)
Deactivate all possible plugins: Did that solve the problem? If it did, it’s most likely a plugin conflict!
Reactivate plugins one at a time until the problem returns. The last plugin activated is the culprit. Report back with that plugin name/link and I can troubleshoot the issue to determine if there’s a fix.
3b. Check for theme conflicts
With all plugins disabled, switch to a bundled theme (2011, 2012, 2013, 2014). Did that solve the problem?
If it did, your theme is causing the issue. Talk to the theme vendor directly if you can. You can also see if the plugin author can work around the theme conflict (but don’t expect them to do this for free).
3c. If it’s not plugins or the theme, it’s likely an issue with your hosting
Yes, really. WordPress runs on top of a lot of other software, and it can’t fix issues with cURL (used to make remote requests), OpenSSL (used for SSL, cryptography), Apache/nginx (the web server software), etc.
Talk to your host to see if they can help you adjust the setting on your server, or move you to more appropriate service.
Note: You may have to switch hosting – there are some terrible hosts with out of date or super locked down software… that likely won’t change (so you have to).
Again, you can also see if the plugin author can work around the hosting conflict (but don’t expect them to do this for free, and switching hosting is usually the cheaper route).