Dear friend!
There are two possible causes:
The logical and physical fibers of the NE are not all connected or are incorrectly connected. Establish complete and correct logical fibers and physical fibers.
The NMS software cannot calculate the route.
You are advised to upload the configuration data of all devices that the service traverses, search for trails, and create trails again.
If the problem persists, manually configure the NE. The path configuration method is not used to configure services.
Good luck!