Problem when I try to add & edit blocks

Hello everyone!

I have a problem when I try to add & edit the blocks of sections, such as: services, projects. When i try to save the changes, the sistem shows me this error message: “The response is not a valid JSON response”.

Someone can help me to solve this problem?

Hey there

Are you using the latest version of the theme and WordPress? can you tell me a version of PHP?
For troubleshooting purposes, please deactivate all your third party plugins and check again

Waiting for your reply

REgards

Yes, I use the latest version of the theme and WordPress.

Version of PHP: PHP 7.4

I deactivated all third party plugins.

But the problem still persists. I tried in all ways to add blocks, but everytime the system shows me this error message:

Even the second way to add blocks doesn’t work. When I click on the button “Add & Edit Services”, or “Add & Edit Projects”, or “Add & Edit Testimonials” nothing happens:

I will be very grateful if we will find the cause of the problem; and the way to fix it.

Best regards