HMC Console Error: "0099 Unknown Error Occurred - Contact Service"

If one HMC has an active 5250 console connection to a partition, an attempt to open another 5250 Console connection to the same partition from a redundant HMC will fail. The error message differs depending on the version of the HMC.

Version 4 Release 2.0 and earlier of the HMC returns the error: 00FF Unknown Error Occurred - Contact Service.

Version 4 Release 2.1 and later of the HMC returns the error: 0008 Session already in use.

In the case of networks with redundant HMCs, only one of the HMCs can have an active console connection. Console sharing (two or more consoles sharing the same session) is only available using the remote 5250 console function through one direct connected HMC.

To resolve the problem, first locate all redundant HMCs. On each redundant HMC, end any active local 5250 console session and any remote 5250 console session connected through that HMC.