cannot set up total cache

Hello,

Thank you for reaching out and I am happy to help!
Something is blocking the Ajax requests. The way this works is that W3 Total Cache is calling Ajax requests over and over and something from the server or some other plugin may be blocking them.
What you can do is to try disabling security plugins and see if that helps. As you can see in the dev tools, network tab when the setup guide is running there is a 404 Ajax requests, and that is the confirmation that something is blocking those requests to the requests limit was hit on the server. This is why you are getting the “Could not update the configuration” error.
The problem can also be a self-signed certificate, fancy permalinks are disabled, or the the php-curl was missing

Thanks!