Uncaught SyntaxError

I reinstalled xampp and now dhtmtlx gantt gives me this error. (Google Chrome)
Uncaught SyntaxError: Unexpected token < in JSON at position 0 and Uncaught TypeError.
This is the error it shows me.

Nevermind, fixed it.

How did you fix this?

Hello Denis,
If you have this issue, please give me more details about your case.
I need a sample of your code to see what might be wrong. You can modify the following snippet:
After you edit the code and see that it reproduces the error, click on the “Share” button and copy the link for the snippet.