This article provides a list of error messages related to the Netskope service and GRE tunnel configuration and explains how to resolve them.
To view the GRE tunnel status and error messages, go to Settings > Security Cloud Platform > GRE Site and hover over 
under Tunnel Status.
NS_ALERT_TENANT_TUNNEL_RESTRICTED
This error occurs when your GRE tunnel is not in service for this Netskope POP because your tenant might be under maintenance. If the issue persists, contact Netskope Support.
NS_ALERT_POP_UNDER_MAINTENANCE
This error occurs when the Netskope POP is not in service because it might be under maintenance. To check the Netskope POP status, see the Netskope Trust Portal. If the issue persists, contact Netskope Support for additional debugging.
NS_ALERT_DOWNSTREAM_SERVICES_HC_FAILURE
This error occurs when there is a failure in the health check from the tunnel gateway towards downstream services (e.g., proxy, Cloud Firewall, etc.).
NS_ALERT_TUNNEL_DOWN_INACTIVE
This error occurs when there are no events received for the GRE tunnel in the last 60 minutes. If the issue persists, contact Netskope Support.
NS_ALERT_TRAFFIC_NOT_SEEN
This error occurs when there is no traffic seen in the GRE tunnel. While the GRE tunnel status is down ; it’s actually active and tunnel status will change to up 
as soon as Netskope receives the traffic.
NS_ALERT_KEEPALIVE_NOT_SEEN
This error occurs when the keepalive/probing packets aren’t seen over the GRE tunnel.
NS_ALERT_INFO_NOT_AVAILABLE
This error occurs when the GRE tunnel is down for an unknown reason, and Netskope doesn’t have any event entry for the respective connection.