Issue With Softaculous apps, error "FastCGI sent in stderr: "Primary script unknown"

[CobraArbok]

In this new VPS there are too many Softaculous applications that do not install properly or that do not start after an installation without error reporting

However, I cannot identify the cause.
In /var/log/apache2 and /var/log/nginx I find nothing significant (I can of course be wrong), while in the domain log I often find the same error.
For example:
Error PC-IP 404 GET /easyapmt/index.php/backend HTTP/2.0
Error PC-IP 8294#0: *337 FastCGI sent in stderr: "Primary script unknown" while reading response header from upstream

This is my VPS.
* Ubuntu 18.04 LTS
* Plesk Onyx Version 17.8.11 Update #60.
* 6 vcore / 12 GB RAM / 240 GB SSD
* In this domain php 7.2.20
* Apache MPM in Event mode
* FPM with Nginx as Reverse Proxy

Thanks in advance for the support.

 

[CobraArbok]

I close the ticket, but I would like to explain.
Obviously I didn't ask here for advice on installing Softaculous.
But I have reported the presence of many errors (over a dozen) almost all the same and that I interpreted as a sign of a server configuration problem.
For this I asked for help and advice, not finding anything useful in the logs (in my humble opinion).
However, finding no response, I close the ticket.
Thanks anyway.