Did anyone manage to resolve this issue as its been a few weeks i got the same error message.
We would really appreciate it if someone can help us on this matter
thank you for your time
You surely have a session permission problem. If you check your /var/log/httpd/error_log you will see that you have an error 13 in the permissions of your zpanel directory.
This is a permission error and I got it long time ago by using mpm-itk in httpd. I had asterisk on the same box and wanted to add zpanel as well to get some domains up. I used itk to have asterisk run under the user "asterisk", while the vhosts run under the "apache".
When you use an additional package which changes the user running your sessions, you get issues like that. My solution was to use mpm-itk and have the zpanel vhost run under root, while asterisk and its web platform were run by user "asterisk" and the other vhosts created by zpanel run by user "apache".
I do not have this problem but, maybe this will help:
Let us know if it does. :)