Scheduler won't appear!

Installed, set in comp, create new user menu (per instructions) but won’t show up…what it could be? (V1.5).

I had to add this to get it working in Firefox:

Maybe it helps at your side too.

Thanks so much for your respond. The problem is not only in FireFox it is in all browsers, computers (PC, Mac). I’m searching now for the requirements (PHP version etc.).

could you give a little more detail ?
For example post your source or explain about the “new user menu (per instructions)” ?