When looking under Network Path Details, the link to Run Diagnostics is greyed out for some Network Paths, indicating that diagnostics are unavailable for them:
Why is this the case?
AppNeta SaaS and Monitoring Point Network Paths
These are TCP paths. You can verify the type of path it is by adding the network protocol column:
Remember that Diagnostics are only ran using ICMP, so underlying network paths using ICMP will be able to run diagnostics.
For alternative when using TCP paths, consider setting up Experience Web Paths. If possible, you may be able to use HTTP workflow to target possible API endpoints.
Learn more about this feature here: