That's probably the right place to start debugging.
If jobs are idle but slots are claimed, that probably means that the negotiator has given slots to jobs -- that is, they match -- but there's a problem activating the claims.
You may want to check that the ShadowLog -- if no shadows are being started, that's one (set of potential) problem(s). If shadows are being started but can't start a job, there should be some information in the ShadowLog about why.
- ToddM