Q:

Cacti is not generating the graphics

I have the cacti installed on the ubuntu 18.04 server and it is not generating the graphics.  All information is -nan (not a number). 
I need to help solve it.  Ask for the configuration files that I'm adding to the post. 

A:

After several attempts and changes in the php files I decided to download the alpha4 version 1.2.0 from Cacti. 
Cacti 1.1.38 is incompatible with php 7.2. 
Follow the link for version 1.2 beta4: https://github.com/Cacti/cacti/archive/develop.zip

