Problem: You get this error in the Admin panel when logging in on performing opertions
There are a few possible causes of the problem, all linked to the Session:
Try reloading your browser to get a fresh token
Try clearing your browser session cookies, Try logging out and back in.
session.secure: true set in Grav's
Ensure you running under SSL using and HTTPS URL if you have
Check that PHP has the correct tmp path set up. This can be set in PHP directly, or by setting Grav's
session.path setting (it can be also set via Admin, in the System Configuration) Reported issue