Title: Plugin causing Critical PHP Errors since update last week Last modified: June 25, 2026 --- # Plugin causing Critical PHP Errors since update last week * [troyw2015](https://wordpress.org/support/users/troyw2015/) * (@troyw2015) * [1 week, 4 days ago](https://wordpress.org/support/topic/plugin-causing-critical-php-errors-since-update-last-week/) * Hi team, * Since your update to Version: 4.7.6 I am getting the following errors. I have turned off all other plugins and tested, but its only when I activate Simple Membership I get these errors in Site Health; * 1 critical issue * Critical issues are items that may have a high impact on your site’s performance or security. Resolving these issues should be prioritised.Page cache is detected but the server response time is still slowPerformance * Page cache enhances the speed and performance of your site by saving and serving static pages instead of calling for a page every time a user visits. * Page cache is detected by looking for an active page cache plugin as well as making three requests to the home page and looking for one or more of the following HTTP client caching response headers:`cache-control`, `expires`, `age`, `last- modified`, `etag`, `via`, `x-cache-enabled`, `x-cache-disabled`, `cf-cache-status`,` x-cache`, `x-litespeed-cache`, `x-srcache-store-status`, `x-srcache-fetch-status`,` x-cache-status`, `x-proxy-cache`, `x-varnish`, `x-lsadc-cache`, `x-qc-cache.` -  Median server response time was 1,586 milliseconds. It should be less than the recommended 600 milliseconds threshold. -  No client caching response headers were detected. -  A page cache plugin was detected. * The page I need help with: _[[log in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fplugin-causing-critical-php-errors-since-update-last-week%2F%3Foutput_format%3Dmd&locale=en_US) to see the link]_ Viewing 4 replies - 1 through 4 (of 4 total) * Plugin Support [mbrsolution](https://wordpress.org/support/users/mbrsolution/) * (@mbrsolution) * [1 week, 3 days ago](https://wordpress.org/support/topic/plugin-causing-critical-php-errors-since-update-last-week/#post-18947731) * Thank you for reaching out to us. Is your server running any type of caching system? Are you running a cache plugin in your site? What PHP version is running in your server? Are you running the latest WordPress version? * The following troubleshooting steps can also help you. * [https://simple-membership-plugin.com/forums/topic/test-for-plugin-and-theme-conflict-before-posting-an-issue-or-a-bug/](https://simple-membership-plugin.com/forums/topic/test-for-plugin-and-theme-conflict-before-posting-an-issue-or-a-bug/) * Kind regards. - This reply was modified 1 week, 3 days ago by [mbrsolution](https://wordpress.org/support/users/mbrsolution/). - This reply was modified 1 week, 3 days ago by [mbrsolution](https://wordpress.org/support/users/mbrsolution/). * Plugin Author [wp.insider](https://wordpress.org/support/users/wpinsider-1/) * (@wpinsider-1) * [1 week, 3 days ago](https://wordpress.org/support/topic/plugin-causing-critical-php-errors-since-update-last-week/#post-18948055) * Thanks for the details. One thing worth clarifying first: the message you’ve pasted isn’t actually a PHP error. It’s the WordPress **Site Health → Performance** check titled _“Page cache is detected but the server response time is still slow.”_ Site Health files that under “critical issues,” but it’s a performance recommendation about server response time, not a PHP fatal error or a code crash. So nothing is broken in the sense of erroring out; Site Health is just reporting that your homepage took ~1,586 ms to respond and that it didn’t see client-side caching headers on its test requests. * The reason it surfaces when Simple Membership is active comes down to how membership plugins work. To enforce content protection and keep member-only pages from being served from a stale cache, Simple Membership sets a login cookie that instructs caching systems (LiteSpeed, etc.) to bypass the cache for the browser holding that cookie. Protected and dynamic member pages therefore can’t be fully cached, which can raise the measured server response time. That’s expected behavior for any access-control plugin rather than a bug introduced in 4.7.6. * A few things that will help: 1. If you’re seeing an _actual_ PHP error somewhere (a fatal error or stack trace), please grab it from your real PHP error log or `wp-content/debug.log` rather than the Site Health screen — the wording there can be misleading. Paste the exact message and we’ll dig in. 2. For the response-time notice, the fix is on the caching/hosting side: make sure your cache plugin is configured to cache public pages normally while excluding your member-only/login/account pages. The slow response time itself is largely a server/hosting performance matter. 3. As a sanity check that 4.7.6 isn’t conflicting with something else, the standard conflict test is worth a quick run: [https://simple-membership-plugin.com/forums/topic/test-for-plugin-and-theme-conflict-before-posting-an-issue-or-a-bug/](https://simple-membership-plugin.com/forums/topic/test-for-plugin-and-theme-conflict-before-posting-an-issue-or-a-bug/) * Thread Starter [troyw2015](https://wordpress.org/support/users/troyw2015/) * (@troyw2015) * [1 week, 3 days ago](https://wordpress.org/support/topic/plugin-causing-critical-php-errors-since-update-last-week/#post-18948469) * Hi team, thanks for your response. * I have gone through the Plugin and Theme conflict process by isolating the plugin by turning off all other plugins, which is how I arrived at your Simple Membership plugin.  I also swapped themes to Twenty Twenty Five and the issues persists. * The website uses Litespeed Cache and as a matter of habit, this was the first plugin I deactivated. When I deactivate it and run Site Health check, it will initially show as good, but when I refresh and run the check again, the ‘Page cache is not detected and the server response time is slow’ warning appears, again and again. * Even with Litespeed Cache active though, I have excluded your /membership-login url and any other urls using your plugin, as well as these cookies; swpm_session and swpm_in_use. * The website is completely up to date with WordPress 7.0 and is hosted on Synergy Wholesale / VentraIP servers, which I find to be extremely reliable and stable. I have tried PHP 8.2, 8.3 and 8.4, but same result with all. Running the debug file did not offer any results and neither did Query Monitor plugin. * The website has never shown this error in the past and I have been using your plugin for several years now, with Litespeed Cache and the same servers. It’s only now that this is happening and only when Simple Membership is active.  * Plugin Support [mbrsolution](https://wordpress.org/support/users/mbrsolution/) * (@mbrsolution) * [1 week, 2 days ago](https://wordpress.org/support/topic/plugin-causing-critical-php-errors-since-update-last-week/#post-18948775) * Thank you for providing more information. However, at present you are the only person reporting this issue. As mentioned above by [@wpinsider-1](https://wordpress.org/support/users/wpinsider-1/), this could be a server side issue and not a plugin issue. Have you spoken to your host support team regarding this PHP error? * Kind regards. Viewing 4 replies - 1 through 4 (of 4 total) You must be [logged in](https://login.wordpress.org/?redirect_to=https%3A%2F%2Fwordpress.org%2Fsupport%2Ftopic%2Fplugin-causing-critical-php-errors-since-update-last-week%2F%3Foutput_format%3Dmd&locale=en_US) to reply to this topic. * ![](https://ps.w.org/simple-membership/assets/icon-128x128.png?rev=974529) * [Simple Membership](https://wordpress.org/plugins/simple-membership/) * [Frequently Asked Questions](https://wordpress.org/plugins/simple-membership/#faq) * [Support Threads](https://wordpress.org/support/plugin/simple-membership/) * [Active Topics](https://wordpress.org/support/plugin/simple-membership/active/) * [Unresolved Topics](https://wordpress.org/support/plugin/simple-membership/unresolved/) * [Reviews](https://wordpress.org/support/plugin/simple-membership/reviews/) * 5 replies * 3 participants * Last reply from: [mbrsolution](https://wordpress.org/support/users/mbrsolution/) * Last activity: [1 week, 2 days ago](https://wordpress.org/support/topic/plugin-causing-critical-php-errors-since-update-last-week/#post-18948775) * Status: not resolved