You get access denied errors on occasion when logging into the cloud portal for Symantec Endpoint Protection 15 using url: (sep.securitycloud.symantec.com) and results in 401 or 404 errors. Sometime when using another browser allows the login.
Symantec is aware of this issue and will update this document when a solution becomes available. It is not necessary to log a support case on this issue. Please subscribe to this article to be notified of any updates.