Purview no application detected.

[Marlon]

Cannot detect application on purview. "Port mirroring does not appear to be set up correctly on gre1"

[Matthew_Hum1]

This means there is no traffic coming in on the GRE tunnel between the Flow Collector/SSA and the Purview appliance.
Please check/post the SSA/FC configuration to ensure that traffic is being mirrored properly.

You can also check the Purview Deployment Guide to compare the configuration against the example deployments.