[Jesse Morse]

After updating Cmap to the most recent version, loading a page on my site that uses it causes this error:

Fatal error: Unknown: Cannot use output buffering in output buffering display handlers in Unknown on line 0

Disabling Cmap allows the page to load, and re-activating it causes the error again.

What should I do to fix this?

[Steven Zahm]

@ Jesse

Do you happen to know from which version you upgraded from? My guess it would have been 5.2.1. The 5.3 update is really only a minor update, there were no large changes. So, that makes this error a bit puzzling.

I did a web search on the error message and they seem to largely related to caching plugins. I see you are running WP Super Cache. Can you try clearing the caches and then deactivating it. Does that clear the error?

[Jesse Morse]

Steven,

Thanks for the reply. I don’t recall the version we were previously using, but we update the plugins pretty regularly – it would have been no more than a month or two since we last updated the plugin, so 5.2.1 most likely would have been the previous version.

I tried deactivating WP Super Cache and clearing the cache as you suggested, and that caused the error message to change to a 500 Internal Server error. Upon examining the site’s error logs in more detail, I found that the original error I mentioned also caused a PHP maximum memory exceeded error. I increased the site’s maximum PHP memory to 256 MB, and now the errors are flipped – a 500 Internal Server error is generated when a cMap page is loaded with Super Cache enabled, and the same error message as before when loading a cMap page with Super Cache cleared and disabled.

[Steven Zahm]

@ Jesse

Could you please create an admin account for me using this plugin so I can take a closer look?

https://wordpress.org/plugins/temporary-login-without-password/

Reply back, as a private replay, with the token login URL.

[Jesse Morse]

This reply has been marked as private.

[Steven Zahm]

@ Jesse

The link does not seem to be valid. I’m not able to login with it.

[Jesse Morse]

This reply has been marked as private.

[Steven Zahm]

@ Jesse

Ok, I’ve managed to narrow down the issue. This being a cMap and/or an output buffering error was a red herring. I’m not even certain this is a Connections issue…

After about an hour or so I tracked a problem displaying the entry logo. After I disable the display of the logo in cMap, everything began working in as far as displaying the directory on the pages is concerned.

I tried editing a few entries. Some only displayed a blank white empty page. I assume these entries have a logo and/or photo attached to them.

Then I tried adding new images to the Media Library and it seems only the smallest of images would actually upload correctly. Normal and large sized images would fail to upload with WordPress reporting a HTTP error. So WP is having trouble with images too. Which would not be surprising that this would affect Connections since Connections uses many of the WP image related functions.

I suspect this may be a PHP memory issue. I see you have that set to 256MB. It is possible to set a high value like this but the web host is enforcing a “hard limit”. Perhaps the web host is actually limiting memory usage to much less than the set 256MB. You’ll have to ask their support team about that.

A couple things to try…

If the web host allows you to choose the PHP version to run on your site in their control panel. I suggest setting it to PHP version 7.1. It runs WP much faster and is far more resource efficient.

You could also try setting the WP_MAX_MEMORY_LIMIT to 256MB or even 512MB.

I hope this helps, let me know!

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