None of our Agents that were previously communicating with the Gateway server that were listed under "agents managed" under the primary management server are showing.  The events that caused this:

1. Gateway server was deleted under "Agent Managed" and removed from the Management Server in error

2. Gateway server was re-added via running the gateway approval tool, now shows as management server and is green/monitored under Management Servers

3. Agents that were on the Gateway servers domain are now no longer communicating with the Gateway, although the Gateway is communicating with the Primary Management server fine (seeing information events 21026/21024 updating configuration information).  All certificates remain the same.

Agent Error messages attempting to connect to Gateway:

The OpsMgr Connector connected to gatewayserver.domain.local, but the connection was closed immediately after authentication occurred.  The most likely cause of this error is that the agent is not authorized to communicate with the server, or the server has not received configuration.  Check the event log on the server for the presence of 20000 events, indicating that agents which are not approved are attempting to connect.

Gateway Error messages related to agents attempting to connect:

A device which is not part of this management group has attempted to access this Health Service. 
Requesting Device Name : agent-server.domain.LOCAL

What was attempted:

1. Reinstall Agent manually / remove agent health state folder, still rejects (the management group is correct)

2. Ensure manual approval of new gateway agents was selected on primary management server, none being shown

3. Reinstall Gateway software on gateway PC, re-run momcertimport and check connectivity, agents still not connecting

4. Clear agent's health state cache from primary management server via monitoring -> ops mgr -> agent health state

Under 'Agents Managed' none of the old agents are showing up, but the Gateway server is.  I can see the old agents under monitoring -> ops mgr -> agent  health state and they're green.  I cannot see the old agents on the administration tab.  I'm not sure what to try next, any assistance would be greatly appreciated.

Thanks,

While attempting to run the powershell command on my primary management server, it does not recognize the agent information input.  These agents are actually connected over the WAN and there is not a trust involved.  If I run a Get-SCOMAgent, it does not list any of the agents that are having issues connecting, so the management server doesn't see them.

PS E:\> Set-SCOMParentManagementServer -Agent (Get-SCOMAgent -Name "agentname.domain.local") -PrimaryServer (Get-SCOM
ManagementServer -Name "gatewayname.domain.local") -WhatIf
Set-SCOMParentManagementServer : Cannot validate argument on parameter 'Agent'. The argument is null or empty. Supply a
n argument that is not null or empty and then try the command again.
At line:1 char:38
+ Set-SCOMParentManagementServer -Agent <<<<  (Get-SCOMAgent -Name "cov-wsus.adcovenant.local") -PrimaryServer (Get-SCO
MManagementServer -Name "gatewayname.domain.local") -WhatIf
    + CategoryInfo          : InvalidData: (:) [Set-SCOMParentManagementServer], ParameterBindingValidationException
    + FullyQualifiedErrorId : ParameterArgumentValidationError,Microsoft.SystemCenter.OperationsManagerV10.Commands.Se
   tSCAgentManagementServerSettingsCommand

Hi,

Please try to set the gateway server with PowerShell method. For details, please refer to:

Set-ManagementServer

http://technet.microsoft.com/en-us/library/gg132251.aspx

Set-SCOMParentManagementServer

http://technet.microsoft.com/en-us/library/hh920210(v=sc.10).aspx

Powershell Commands to configure Gateway Server / Agent Failover

http://blogs.technet.com/b/jimmyharper/archive/2010/07/23/powershell-commands-to-configure-gateway-server-agent-failover.aspx

Thanks.

Did you look in pending management?  

Would also think they should be getting into Pending Management. Also check the scom admin pane -> settings -> server -> security and check wether the second option is selected (with or without the checkbox below it).