Check the Discovery Progress window

In the Domain Manager Administration Console, click Topology > Show Discovery Progress to launch the Discovery Progress window. The Discovery Progress window is shown in GUID-1E74939B-A6F3-4B17-A0BA-3527F3ACC04C.html#GUID-1E74939B-A6F3-4B17-A0BA-3527F3ACC04C___MPLS_DISCO_RESOLVE_85066.

Check the messages on the Pending Elements list and in the Discovery Status section of the window.

Each entry on the Pending Elements list has an accompanying comment that describes the discovery error. And in some cases, just below the Discovery Status section in the Discovery Progress window, a message will appear that explains the discovery error.