Composite/live connection stopped working overnight

[LEggbbK]

At some point in the last 16 hours, live connections to any existing semantic model stopped working, at least within our org. 

- In Power BI Services and on Desktop, existing reports with composite models aren't able to display any visuals with measures linked to those models. Reports directly linked to their own semantic models still work in Desktop and in Services.

- In Power BI Desktop, it is impossible to connect to any existing semantic model, or to change existing connections. This results in "MWC token validation failed" errors.

Error log when attempting to connect to change a connection in an existing composite model:

Feedback Type:
Frown (Error)

Error Message:
MWC token validation failed: Microsoft.IdentityModel.Tokens.SecurityTokenSignatureKeyNotFoundException at Microsoft.IdentityModel.JsonWebTokens.JsonWebTokenHandler.ValidateSignature(JsonWebToken jwtToken, TokenValidationParameters validationParameters, BaseConfiguration configuration)
at Microsoft.IdentityModel.JsonWebTokens.JsonWebTokenHandler.ValidateSignatureAndIssuerSecurityKey(JsonWebToken jsonWebToken, TokenValidationParameters validationParameters, BaseConfiguration configuration)
at Microsoft.IdentityModel.JsonWebTokens.JsonWebTokenHandler.<ValidateJWSAsync>d__69.MoveNext()

Technical Details:
RootActivityId: a39568d3-1a5a-4418-9882-c42655e35e86
Date (UTC): 7/19/2024 8:26:02 AM

Stack Trace:
Microsoft.AnalysisServices.AdomdClient.AdomdConnectionException
at Microsoft.AnalysisServices.AdomdClient.HttpStream.HttpChannelController.GetResponseMessageImpl(HttpStream owner, Object context, Task`1 pendingResponse)
at Microsoft.AnalysisServices.AdomdClient.HttpStream.HttpChannelController.CompleteHttpClientBasedOperation(HttpStream owner, Object context, Task`1 pendingResponse)
at Microsoft.AnalysisServices.AdomdClient.HttpStream.HttpXmlaOperation.HttpClientOperationManager.GetResponse(HttpXmlaOperation operation)
at Microsoft.AnalysisServices.AdomdClient.HttpStream.PaasInfraController.PaasInfraXmlaOperation.EnsureCanRead()
at Microsoft.AnalysisServices.AdomdClient.HttpStream.HttpXmlaOperation.GetResponseDataType()
at Microsoft.AnalysisServices.AdomdClient.HttpStream.GetResponseDataType()
at Microsoft.AnalysisServices.AdomdClient.CompressedStream.GetResponseDataType()
at Microsoft.AnalysisServices.AdomdClient.XmlaClient.EndRequest(Boolean useBinaryXml)
at Microsoft.AnalysisServices.AdomdClient.XmlaClient.CreateSession(ListDictionary properties, Boolean sendNamespaceCompatibility, String sessionToken)
at Microsoft.AnalysisServices.AdomdClient.AdomdConnection.XmlaClientProvider.Microsoft.AnalysisServices.AdomdClient.AdomdConnection.IXmlaClientProviderEx.CreateSession(Boolean sendNamespaceCompatibility)
at Microsoft.AnalysisServices.AdomdClient.AdomdConnection.ConnectToXMLA(Boolean createSession, Boolean isHTTP)
at Microsoft.AnalysisServices.AdomdClient.AdomdConnection.Open()
at Microsoft.PowerBI.Client.Windows.AnalysisServices.Connection.AdomdQueryExecutor.OpenConnectionAndExecute[T](IAdomdConnectionPool connectionPool, IAdomdConnectionFactory connectionFactory, String connectionString, QueryExecutionOptions executionOptions, IPowerBITelemetryService telemetry, Func`2 execute)
at Microsoft.PowerBI.Client.Windows.LiveConnectHelpers.AnalysisServices.ASLiveExternalService.ExecuteCommand[T](String name, Func`2 execute)
at Microsoft.PowerBI.Client.Windows.LiveConnectHelpers.PowerBIService.PowerBIServiceLiveConnectionProperties.GetDatabasesAndCubes()
at Microsoft.PowerBI.Client.Windows.LiveConnectHelpers.ProxyModelConnectionCompleter.CompleteConnectionPropertiesIfNecessary(ILiveConnectionProperties connectionProperties, IPowerBIWindowService windowService)
at Microsoft.PowerBI.Client.Windows.FloatingDialog.KoManageDataSourcesDialog.<ChangeSourceForPowerBIDataset>d__48.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.PowerBI.Client.Windows.IExceptionHandlerExtensions.<HandleAwaitableAsyncExceptions>d__1.MoveNext()

Stack Trace Message:
MWC token validation failed: Microsoft.IdentityModel.Tokens.SecurityTokenSignatureKeyNotFoundException at Microsoft.IdentityModel.JsonWebTokens.JsonWebTokenHandler.ValidateSignature(JsonWebToken jwtToken, TokenValidationParameters validationParameters, BaseConfiguration configuration)
at Microsoft.IdentityModel.JsonWebTokens.JsonWebTokenHandler.ValidateSignatureAndIssuerSecurityKey(JsonWebToken jsonWebToken, TokenValidationParameters validationParameters, BaseConfiguration configuration)
at Microsoft.IdentityModel.JsonWebTokens.JsonWebTokenHandler.<ValidateJWSAsync>d__69.MoveNext()

Technical Details:
RootActivityId: a39568d3-1a5a-4418-9882-c42655e35e86
Date (UTC): 7/19/2024 8:26:02 AM

PowerBINonFatalError:
{"AppName":"PBIDesktop","AppVersion":"2.131.901.0","ModuleName":"Microsoft.PowerBI.AdomdClient.dll","Component":"Microsoft.AnalysisServices.AdomdClient.HttpStream+HttpChannelController","Error":"Microsoft.AnalysisServices.AdomdClient.AdomdConnectionException","MethodDef":"GetResponseMessageImpl","ErrorOffset":"74","ErrorCode":""}

Model Default Mode:
Composite

Model Version:
PowerBI_V3


Enabled Preview Features:
PBI_sparklines
PBI_scorecardVisual
PBI_NlToDax
PBI_fieldParametersSuperSwitch
PBI_onObject
PBI_setLabelOnExportPdf
PBI_dynamicFormatString
PBI_oneDriveSave
PBI_oneDriveShare
PBI_useModernPublishDialogs
PBI_gitIntegration
PBI_newCard
PBI_buttonSlicerAuthoring
PBI_EimLessElevatedUser
PBI_mobileAutoReportLayout
PBI_daxInlineCopilot
PBI_aiNarrativesVisual
PBI_generateMeasureDescriptionsButton
PBI_visualCalculationsAuthoring
PBI_desktopReportAuthoringCopilot

Disabled Preview Features:
PBI_shapeMapVisualEnabled
PBI_SpanishLinguisticsEnabled
PBI_qnaLiveConnect
PBI_b2bExternalDatasetSharing
PBI_enhancedTooltips
PBI_publishDialogsSupportSubfolders
PBI_tmdlInDataset
PBI_enhancedReportFormat
PBI_qnaImproveLsdlCopilot

Disabled DirectQuery Options:
TreatHanaAsRelationalSource

Cloud:
GlobalCloud

Code:
MwcTokenValidationException

RootActivityId:
a39568d3-1a5a-4418-9882-c42655e35e86

UtcDate:
7/19/2024 8:26:02 AM

HttpStatusCode:
401

SubCode:
0

PowerBIUserFeedbackServices_IsReported:
True

When attempting to connect to an existing semantic model from a fresh file:

Feedback Type:
Frown (Error)

Timestamp:
2024-07-19T07:58:38.1150898Z

Local Time:
2024-07-19T09:58:38.1150898+02:00

Session ID:
6d23f2fd-45d2-4288-be4a-52412d5ad0d6

Release:
July 2024

Product Version:
2.131.901.0 (24.07) (x64)

Stack Trace:
Microsoft.AnalysisServices.AdomdClient.AdomdConnectionException
at System.Windows.Forms.Control.MarshaledInvoke(Control caller, Delegate method, Object[] args, Boolean synchronous)
at System.Windows.Forms.Control.Invoke(Delegate method, Object[] args)
at System.Windows.Forms.WindowsFormsSynchronizationContext.Send(SendOrPostCallback d, Object state)
at Microsoft.PowerBI.Client.Windows.Services.UIBlockingService.SetUIBlockingStateToAllowModalDialogs(Action action)
at Microsoft.PowerBI.Client.Windows.LiveConnectHelpers.LiveConnectionPropertiesValidator.TryGetValidLiveConnectionProperties(IPowerBIWindowService windowService, ILiveConnectionProperties connectionProperties, Report report, ILiveConnectionCompleter liveConnectionPropertiesCompleter, ILiveConnectionProperties& validLiveConnectionProperties, Boolean& resultIsSameConnection, ValidationStatus& validationStatus)
at Microsoft.PowerBI.Client.Windows.PowerBIDataImporter.AreAnalysisServicesConnectionPropertiesValid(IPowerBIWindowService windowService, Report report, ILiveConnectionProperties connectionProperties, AnalysisServicesConnectionMode connectionMode, ILiveConnectionCompleter completer, ILiveConnectionProperties& validConnectionProperties)
at Microsoft.PowerBI.Client.Windows.PowerBIDataImporter.ValidateAndCreateAnalysisServicesConnection(ILiveConnectionProperties connectionProperties, Boolean addToFormulaHistory, Boolean isExternalDataset)
at Microsoft.PowerBI.Client.Windows.PowerBIDataImporter.<>c__DisplayClass35_0.<<AddPowerBIDatahubSource>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at Microsoft.PowerBI.Client.Windows.IExceptionHandlerExtensions.<HandleAwaitableAsyncExceptions>d__1.MoveNext()

PowerBINonFatalError:
{"AppName":"PBIDesktop","AppVersion":"2.131.901.0","ModuleName":"Microsoft.PowerBI.Client.Windows.dll","Component":"Microsoft.PowerBI.Client.Windows.Services.UIBlockingService","Error":"Microsoft.AnalysisServices.AdomdClient.AdomdConnectionException","MethodDef":"SetUIBlockingStateToAllowModalDialogs","ErrorOffset":"43","ErrorCode":""}

OS Version:
Microsoft Windows NT 10.0.22621.0 (x64 en-US)

CLR Version:
4.8 or later [Release Number = 533320]

Peak Virtual Memory:
70.7 GB

Private Memory:
596 MB

Peak Working Set:
0.976 GB

IE Version:
11.1.22621.0

User ID:
31b88c78-384f-431b-a3a0-916d1606c368

Workbook Package Info:
1* - en-CH, Query Groups: 0, fastCombine: Disabled, runBackgroundAnalysis: False.

Telemetry Enabled:
True

Model Default Mode:
Composite

Model Version:
PowerBI_V3

Enabled Preview Features:
PBI_sparklines
PBI_scorecardVisual
PBI_NlToDax
PBI_fieldParametersSuperSwitch
PBI_onObject
PBI_setLabelOnExportPdf
PBI_dynamicFormatString
PBI_oneDriveSave
PBI_oneDriveShare
PBI_useModernPublishDialogs
PBI_gitIntegration
PBI_newCard
PBI_buttonSlicerAuthoring
PBI_EimLessElevatedUser
PBI_mobileAutoReportLayout
PBI_daxInlineCopilot
PBI_aiNarrativesVisual
PBI_generateMeasureDescriptionsButton
PBI_visualCalculationsAuthoring
PBI_desktopReportAuthoringCopilot

Disabled Preview Features:
PBI_shapeMapVisualEnabled
PBI_SpanishLinguisticsEnabled
PBI_qnaLiveConnect
PBI_b2bExternalDatasetSharing
PBI_enhancedTooltips
PBI_publishDialogsSupportSubfolders
PBI_tmdlInDataset
PBI_enhancedReportFormat
PBI_qnaImproveLsdlCopilot

Disabled DirectQuery Options:
TreatHanaAsRelationalSource

Cloud:
GlobalCloud

DPI Scale:
150%

Supported Services:
Power BI

[v-xiaoyan-msft]

Hi @LEggbbK ,

We failed to reproduce this issue, and for the time being, there is no feedback from other users who have had a similar experience to yours.

Based on the above information, this issue is complex which may need to collect log files for further troubleshooting. Since community support engineers don't have that access, I would suggest opening a Support Ticket. If you are a Power BI Pro or Fabric licensee, you can create a support ticket for free and a dedicated Microsoft engineer will come to solve the problem for you. 
It would be great if you continue to share in this issue to help others with similar problems after you know the root cause or solution.

The link of Power BI Support: Support | Microsoft Power BI

For how to create a support ticket, please refer to How to create a support ticket in Power BI - Microsoft Power BI Community

Best Regards,
Community Support Team _ Caitlyn