1. Advised to Clear cache and cookies. Please see below article on how to clear cache and cookies.
Clear Cache and Cookies in Firefox
Clear Cache and Cookies in Chrome
Clear Cache and Cookies in Internet Explorer
2. Reboot/Restart the PC/laptop/Desktop.
3. If will still get a same error response when editing a session, please contact Support for further assistance.
3. If will still get a same error response when editing a session, please contact Support for further assistance.