What can cause an undefined function error?

  • Resolved drokkon

    (@drokkon)


    11 years, 9 months ago

    I’m consistently receiving fatal errors on all sites in my multisite installation. They occur as a “Call to undefined function” to is_plugin_active_for_network(), add_menu_page(), and set_screen_options().

    The first two exist (and they do) in wp-admin/includes/plugin.php. The third exists in wp-admin/includes/misc.php.

    What causes this?

Viewing 7 replies - 16 through 22 (of 22 total)
  • Thread Starter drokkon

    (@drokkon)

    Yes, all of my sites reside on the same VPS with one IP address.

    Like I said, Cloudflare CDN doesn’t seem to accomplish anything, as my sites were all still PAINFULLY slow. So I tried W3TC. But even W3TC is made to work with CDNs including Cloudflare, so obviously a CDN doesn’t negate the need for caching.

    Fixing the .htaccess file didn’t help. Maybe I need to reboot Apache.

    Thread Starter drokkon

    (@drokkon)

    No joy.

    so obviously a CDN doesn’t negate the need for caching.

    Please study that statement.

    Thread Starter drokkon

    (@drokkon)

    Thanks for your help tonight.

    YW.

    @drokkon, please send me an email through my site so that I can have a look at your particular situation please.

    Thread Starter drokkon

    (@drokkon)

    Thanks, Frederick, for your response.

    Unfortunately, I ended up completely nuking the VPS, rebuilding it, and then restoring both cPanel accounts. That fixed the fatal errors, so I have no idea what the problem was.

    So now I have two multisite installations running on a fresh VPS. The one that I uninstalled W3TC from is now running like a dream. The one with W3TC still installed still runs slowly!

    If you’d like to have a look, let me know and I’ll give you access.

Viewing 7 replies - 16 through 22 (of 22 total)
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