Site Health – cURL issues

For the loopback error/issue. It means that your site cannot connect back to itself at /wp-cron.php and/or /wp-admin/admin-ajax.php. If you had supplied the URL of the site in question, I may have be able to help determine what is causing that. But without that I can only suggest that you make sure that you’re not using any security implementations to block access to either of those files.

It could also be caused a plugin. To check for a plugin conflict you can temporarily deactivate all other plugins, and then see if it works better. If so, then you now know that one or more of the plugins were conflicting and you can reactivate the plugins one at a time to find which one(s) causes the conflict. Check any maintenance mode, safe mode, calendar, security, cron control, minifying, or caching plugins first (for caching plugins you may need to also clear its cache when deactivating it to make sure it counts).

Also, check in the wp-config.php file to make sure there isn’t a ‘define’ disabling the wp-cron and/or a ‘timeout’.
define('DISABLE_WP_CRON', true);
and/or:
define('WP_CRON_LOCK_TIMEOUT', 120);

Editing wp-config.php

Finally, if your host uses mod_security, please check with them to make sure they are not blocking the cron loopback. Another thing to check would be if you’re using a CDN like Cloudflare. Cloudflare may be blocking the connection/process and you may need to seek their support to verify. Another example is that some people like to password protect their wp-admin directory with .htaccess but forget to allow HTTP access for admin-ajax.php, which is located in the wp-admin directory and required for WordPress and plugins to utilize the WordPress cron task scheduling system correctly.

@thomas4ithemes

Thanks for replying, and thanks for your detailed response.

The website in question is here: [ expanded and move to link field ]

I did as you suggested and deactivated all plugins,
reactivating them one by one
and then refreshing the ../wp-admin/site-health.php page.

I discovered two plugins were at fault:

https://getbooked.io/

and

https://www.ads-software.com/plugins/wordfence/

I’ve kept both deactivated and will open tickets with both developers.

If you’re able to deduce anything else it would be greatly appreciated.

Kind Regards.

• This reply was modified 4 years, 11 months ago by Jan Dembowski.

@lordliverpool Don’t use short links on this site, those get expanded when found and I have expanded yours.

I’ve also moved the link to the link field, that field is only viewable by logged in users. It does not show up on search engine hits.

BTW

I just checked the site-health page again and I got this cURL error:

Image Here:
https://hosting.photobucket.com/images/i395/LordLiverpool/Annotation%202020-04-27%20132703.png?width=1920&height=1080&fit=bounds

Text Here:

A scheduled event is late
Performance
The scheduled event, jetpack_sync_cron, is late to run. Your site still works, but this may indicate that scheduling posts or automated updates may not work as intended.

An error occurred while checking whether your site can be found by search engines
SEO
Ryte offers a free indexability check for Yoast SEO users. The request to Ryte to check whether your site can be found by search engines failed due to an error.

Error details: cURL error 28: Operation timed out after 5000 milliseconds with 0 bytes received (http_request_failed)
If this is a live site, it is recommended that you figure out why the check failed.(Opens in a new browser tab)

Go to Ryte to analyze your entire site

So something else is at play here.

Thanks @jdembowski

I was obfuscating the URL with Bitly as there was no option to retrospectively add the site’s URL.

A feature request for the forum.

It won’t happen. ??

*Drinks coffee*

Obfuscating links has been (as you may imagine) well and truly abused in the past. As a compromise the link field is used in the opening post. Some people don’t want their link in SERP so that field can only be viewed by real users who are logged into the site.

• This reply was modified 4 years, 11 months ago by Jan Dembowski. Reason: Grammar

@jdembowski haha well thanks for your honest answer! ??
and thanks for editing my link, it’s appreciated.

@thomas4ithemes I greatly appreciate the suggestions for getting to the bottom of that error. I went round and round and in the end it was mod_security. We disabled it completely and my sysAdmin assured me other security measures were in place so that mod_security was not needed.

So did anybody fix this problem? I still got the problem running a docker container of wordpress latest version with Cloudflare. And literally every CURL request is failing.

Site Health is showing me an error with the REST API:
cURL error 28: Operation timed out after 10004 milliseconds with 0 bytes received

Also scheduled events fail.

@lordliverpool any fix?

• This reply was modified 4 years, 5 months ago by cptdaydreamer.

@jdembowski
I no longer get emails from www.ads-software.com when someone posts on one of my forum threads. Should I open a new thread for that issue???

@cptdaydreamer
Sorry, I never fixed this problem. I still get the same and/or similar error messages sporadically across my different WordPress installations, despite them all being on the same physical web server. There seems to be no discernable pattern to the problem, not that I can determine anyway!

Even today I got these error messages:
Click here to see screenshot 1 on SnipBoard.io

Loopback requests are used to run scheduled events, and are also used by the built-in editors for themes and plugins to verify code stability.

The loopback request to your site failed, this means features relying on them are not currently working as expected.
Error: cURL error 28: Operation timed out after 10000 milliseconds with 0 bytes received (http_request_failed)

Click here to see screenshot 2 on SnipBoard.io

The scheduled event, action_scheduler_run_queue, is late to run. Your site still works, but this may indicate that scheduling posts or automated updates may not work as intended.

I stumbled upon this great article:
https://www.dedoimedo.com/computers/wordpress-site-health-curl-error-28.html

TL;DR
Basically he says not to worry about it.

Cheers