Enterprise 11.1 Portal log error: unreachable hosting server?

[ErinMara]

We've been having some connection or performance issues on our Enterprise 11.1 deployment, and when I review errors I'm finding this in my Portal logs:

"Using defaults for some properties of the self resource (ex: supportsSceneServices). The hosting server may not be reachable."

Has anyone else seen this and resolved it?

[dgiersz_cuyahoga]

We also regularly see this error. I have always assumed it is because we do not have a tile cache data store, which is required for 3D scenes.