When I click on Notifications, I receive this error message - Not Acceptable!
An appropriate representation of the requested resource could not be found on this server. This error was generated by Mod_Security.
It's part of your configurable webserver environment.
Ask your provider to either disable the module completely or to add a rule which would allow Ossn notifications to pass.
Actually, Ossn doesn't need it.
I have no idea what mod_security is. Is that something easy to delete?