WSUS Update Services MMC Console - Error: Connection Error

Do an IISRESET /NOFORCE from command prompt. Probably one of the Application Pools crashed which should be reflected in your event logs.

Try again after the IISRESET and see how you go. This would be on the WSUS server btw.

Sorry - that didn't resolve the issue.

Is the WSUS working at all and you're just having a hard time connecting or WSUS is broken?

If WSUS doesn't work and/or if there are too many things wrong with it then your best bet is to reinstall it.

http://www.channelpronetwork.com/article/reinstalling_wsus_on_sbs_2008_and_2011_too

https://www.experts-exchange.com/questions/24646666/How-do-I-fix-repair-WSUS-3-0-SP1-on-SBS-2008.html

In your event logs, have a look for warnings and errors related to WSUS on the WSUS server, see if it mentions anything in particular.

Also have a look at whether this article applies. If nothing apparent in logs and article does not work you could indeed look at repairing WSUS in full.

Log Name:      Application
Source:        Windows Server Update Services
Date:          26/11/2015 5:25:12 PM
Event ID:      7032
Task Category: None
Level:         Warning
Keywords:      Classic
User:          N/A
Computer:      TMGS02.contoso.local
Description:
The WSUS administration console was unable to connect to the WSUS Server via the remote API.

Verify that the Update Services service, IIS and SQL are running on the server. If the problem persists, try restarting IIS, SQL, and the Update Services Service.

System.Net.WebException -- The operation has timed out

Source
System.Web.Services

Stack Trace:
   at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request)
   at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request)
   at Microsoft.UpdateServices.Internal.DatabaseAccess.ApiRemotingCompressionProxy.GetWebResponse(WebRequest webRequest)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
   at Microsoft.UpdateServices.Internal.ApiRemoting.ExecuteSPGetUpdateServerStatus(Int32 updateSources, Boolean includeDownstreamComputers, String updateScopeXml, String computerTargetScopeXml, String preferredCulture, Int32 publicationState, Int32 propertiesToGet)
   at Microsoft.UpdateServices.Internal.DatabaseAccess.AdminDataAccessProxy.ExecuteSPGetUpdateServerStatus(UpdateSources updateSources, Boolean includeDownstreamComputers, String updateScopeXml, String computerTargetScopeXml, String preferredCulture, ExtendedPublicationState publicationState, UpdateServerStatusPropertiesToGet propertiesToGet)
   at Microsoft.UpdateServices.Internal.BaseApi.UpdateServer.GetStatus(UpdateSources updateSources, Boolean includeDownstreamComputers, UpdateScope updatesToInclude, ComputerTargetScope computersToInclude, UpdateServerStatusPropertiesToGet propertiesToGet)
   at Microsoft.UpdateServices.Internal.BaseApi.UpdateServer.GetReplicaStatus(UpdateSources updateSources)
   at Microsoft.UpdateServices.UI.SnapIn.Common.CachedUpdateServerStatus.GetFreshObjectForCache()
   at Microsoft.UpdateServices.UI.AdminApiAccess.CachedObject.GetFromCache()
   at Microsoft.UpdateServices.UI.SnapIn.Pages.ServerSummaryPage.backgroundWorker_DoWork(Object sender, DoWorkEventArgs e)
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Windows Server Update Services" />
    <EventID Qualifiers="0">7032</EventID>
    <Level>3</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2015-11-26T06:25:12.000Z" />
    <EventRecordID>5137000</EventRecordID>
    <Channel>Application</Channel>
    <Computer>TMGS02.contoso.local</Computer>
    <Security />
  </System>
  <EventData>
    <Data>The WSUS administration console was unable to connect to the WSUS Server via the remote API.

Verify that the Update Services service, IIS and SQL are running on the server. If the problem persists, try restarting IIS, SQL, and the Update Services Service.

System.Net.WebException -- The operation has timed out

Source
System.Web.Services

Stack Trace:
   at System.Web.Services.Protocols.WebClientProtocol.GetWebResponse(WebRequest request)
   at System.Web.Services.Protocols.HttpWebClientProtocol.GetWebResponse(WebRequest request)
   at Microsoft.UpdateServices.Internal.DatabaseAccess.ApiRemotingCompressionProxy.GetWebResponse(WebRequest webRequest)
   at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
   at Microsoft.UpdateServices.Internal.ApiRemoting.ExecuteSPGetUpdateServerStatus(Int32 updateSources, Boolean includeDownstreamComputers, String updateScopeXml, String computerTargetScopeXml, String preferredCulture, Int32 publicationState, Int32 propertiesToGet)
   at Microsoft.UpdateServices.Internal.DatabaseAccess.AdminDataAccessProxy.ExecuteSPGetUpdateServerStatus(UpdateSources updateSources, Boolean includeDownstreamComputers, String updateScopeXml, String computerTargetScopeXml, String preferredCulture, ExtendedPublicationState publicationState, UpdateServerStatusPropertiesToGet propertiesToGet)
   at Microsoft.UpdateServices.Internal.BaseApi.UpdateServer.GetStatus(UpdateSources updateSources, Boolean includeDownstreamComputers, UpdateScope updatesToInclude, ComputerTargetScope computersToInclude, UpdateServerStatusPropertiesToGet propertiesToGet)
   at Microsoft.UpdateServices.Internal.BaseApi.UpdateServer.GetReplicaStatus(UpdateSources updateSources)
   at Microsoft.UpdateServices.UI.SnapIn.Common.CachedUpdateServerStatus.GetFreshObjectForCache()
   at Microsoft.UpdateServices.UI.AdminApiAccess.CachedObject.GetFromCache()
   at Microsoft.UpdateServices.UI.SnapIn.Pages.ServerSummaryPage.backgroundWorker_DoWork(Object sender, DoWorkEventArgs e)</Data>
  </EventData>
</Event>

Log Name:      Application
Source:        Windows Server Update Services
Date:          26/11/2015 5:25:13 PM
Event ID:      7053
Task Category: None
Level:         Error
Keywords:      Classic
User:          N/A
Computer:      TMGS02.contoso.local
Description:
The WSUS administration console has encountered an unexpected error. This may be a transient error; try restarting the administration console. If this error persists,

Try removing the persisted preferences for the console by deleting the wsus file under %appdata%\Microsoft\MMC\.


System.NullReferenceException -- Object reference not set to an instance of an object.

Source
Microsoft.UpdateServices.UI.SnapIn

Stack Trace:
   at Microsoft.UpdateServices.UI.SnapIn.Pages.ServerSummaryPage.backgroundWorker_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e)
Event Xml:
<Event xmlns="http://schemas.microsoft.com/win/2004/08/events/event">
  <System>
    <Provider Name="Windows Server Update Services" />
    <EventID Qualifiers="0">7053</EventID>
    <Level>2</Level>
    <Task>0</Task>
    <Keywords>0x80000000000000</Keywords>
    <TimeCreated SystemTime="2015-11-26T06:25:13.000Z" />
    <EventRecordID>5137001</EventRecordID>
    <Channel>Application</Channel>
    <Computer>TMGS02.contoso.local</Computer>
    <Security />
  </System>
  <EventData>
    <Data>The WSUS administration console has encountered an unexpected error. This may be a transient error; try restarting the administration console. If this error persists,

Try removing the persisted preferences for the console by deleting the wsus file under %appdata%\Microsoft\MMC\.


System.NullReferenceException -- Object reference not set to an instance of an object.

Source
Microsoft.UpdateServices.UI.SnapIn

Stack Trace:
   at Microsoft.UpdateServices.UI.SnapIn.Pages.ServerSummaryPage.backgroundWorker_RunWorkerCompleted(Object sender, RunWorkerCompletedEventArgs e)</Data>
  </EventData>
</Event>

The two error messages in the event log are above.

I've tried clearing :
appdata%\Microsoft\MMC\.

but it didn't solve the problem.