I was the one who installed the Linux Apache and Mysql server. Mod_security is not enabled
The error happens when I first click on the tasks tab and then go to the related ticket tab.
Now, when I don't go through the task tab, the error doesn't happen.
I did other tests but the error really exists.
I don't have that much programming knowledge but I'll keep trying.
I need to be able to resolve this issue to deploy the sticket to a client.
I did a lot of tests and everything else seems to be ok.
Thank you