ERROR Updating failed. Error message: The response is not a valid JSON response.

Editing /etc/apache2/apache2.conf and changing

AllowOverride None
to
AllowOverride All for /var/www.

Solved this for me.

Followed this amazing guide for installing WP on a Raspberry:
https://projects.raspberrypi.org/en/projects/lamp-web-server-with-wordpress/7

And in the end you are told to change the same thing in:
/etc/apache2/sites-available/000-default.conf

But I also had to change it in the first file mentioned here. Now everything works!

• This reply was modified 3 years, 7 months ago by eriklanden.

OMG!!! I have been searching for a solution for MONTHS!!
In another thread someone posted this:

“So I was able to figure this out!

I called my hosting provider (GoDaddy) and they said it was due to my Security Package not allowing my IP address to go through.

All I had to do was add my IP address to the firewall whitelist and then I was able to edit pages again!

TRY IT! ”

SOLUTION:

I whitelisted my IP (which must have changed at some point) with my security provider (sucuri.com) and it solved my problem! Finally!

So happy!!

In my case, I have created a child theme, in function.php I have written some custom code for excerpt and read more, that causes edit/update problem

• This reply was modified 3 years, 6 months ago by soumyavg.

Just a data point, no idea if this will help anyone: I was repeatedly getting this error when trying to update a specific page. Updating Permalinks didn’t fix it. The error seemed to be caused by a paragraph containing the word “database(s)”. When I changed it to just “databases”, I stopped getting the error.

Big thanks to @agentsully — I was able to quickly add myself to the sucuri firewall whitelist and continue to edit my pages.

thank you!

Looks like your question was answered in a comment https://make.www.ads-software.com/core/2021/06/25/introducing-theme-json-in-wordpress-5-8/#comment-41667 some hours ago, but adding a link so it’s visible for those who are looking for the same information.

Hi everyone. My site had been suffering from this issue for several months until yesterday. I wasn’t able to update my pages and add widgets to my footer and header. I could not find a solution anywhere on the internet, so I felt I have to post the solution I found.

This issue was related to the ModSecurity tool.

ModSecurity is an Apache module that works as a web application firewall. It blocks known exploits and protects from a range of attacks against web applications. However, sometimes, mod_security may incorrectly determine that a certain request is malicious while it is actually legitimate. In such situations, you can whitelist the triggered mod_security rule on the server so that you can bypass the block. I contacted my hosting, explained the situation, and they whitelisted all the rules that were being blocked by ModSecurity incorrectly.

They did it in a matter of minutes, and everything worked!

Everyone on this topic, from a moderator:

This topic is overloaded with “me, too” responses. If you need support then per the forum guidelines please start your own topic.

A lot more people will see your post, and that way you stand a good chance of getting the assistance you want. Despite any similarity in symptoms, your issue is likely to be completely different because of possible differences in physical servers, accounts, hosts, plugins, theme, configurations, etc. Thus one problem, on one setup is not indicative of the functionality and reliability of an application as a whole.

https://www.ads-software.com/support/forum-user-guide/faq/#i-have-the-same-problem-can-i-just-reply-to-someone-elses-post-with-me-too

https://www.ads-software.com/support/guidelines/#post-in-the-best-place

You can do so here:

https://www.ads-software.com/support/forum/how-to-and-troubleshooting/#new-post

This topic is now closed.

Thanks.