Error: Connecting to SharePoint Online (SPO Tenant) - An error occurred during the operation of a service method: Could not connect to remote SharePoint server (4331813)

You may see one of the following errors when when connecting to SharePoint Online from Content Matrix:

Error: An error occurred during the operation of a service method: Could not connect to remote SharePoint server: 'https://M365EDU096662-admin.sharepoint.com'. Unable to obtain SharePoint Online authentication cookie. No result was returned. Stack: at Metalogix.SharePoint.Adapters.CSOM2013.CSOMAdapter.CheckConnection() at SyncInvokeCheckConnection(Object , Object[] , Object[] ) at System.ServiceModel.Dispatcher.SyncMethodInvoker.Invoke(Object instance, Object[] inputs, Object[]& outputs) at System.ServiceModel.Dispatcher.DispatchOperationRuntime.InvokeBegin(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage5(MessageRpc& rpc) at System.ServiceModel.Dispatcher.ImmutableDispatchRuntime.ProcessMessage11(MessageRpc& rpc) at System.ServiceModel.Dispatcher.MessageRpc.Process(Boolean isOperationContextSet) Type: Metalogix.SharePoint.Adapters.ServiceError HResult:-2146233088

                                                      OR

Error: Cannot contact web site 'https://m365x616628-admin.sharepoint.com/' or the web site does not support SharePoint Online credentials. The response status code is 'Unauthorized'. The response headers are 'X-SharePointHealthScore=2, X-MSDAVEXT_Error=917656; Access+denied.+Before+opening+files+in+this+location%2c+you+must+first+browse+to+the+web+site+and+select+the+option+to+login+automatically., SPRequestGuid=48ad4a9f-f0cb-0000-48e2-8f858d95d272, request-id=48ad4a9f-f0cb-0000-48e2-8f858d95d272, MS-CV=n0qtSMvwAABI4o+FjZXScg.0, Strict-Transport-Security=max-age=31536000, SPRequestDuration=50, SPIisLatency=0, MicrosoftSharePointTeamServices=16.0.0.20008, X-Content-Type-Options=nosniff, X-MS-InvokeApp=1; RequireReadOnly, X-MSEdge-Ref=Ref A: 50D37E642A284A00A983D6EE041F6854 Ref B: CH1EDGE1008 Ref C: 2020-04-20T17:34:19Z, Content-Length=0, Content-Type=text/plain; charset=utf-8, Date=Mon, 20 Apr 2020 17:34:19 GMT, P3P=CP="ALL IND DSP COR ADM CONo CUR CUSo IVAo IVDo PSA PSD TAI TELo OUR SAMo CNT COM INT NAV ONL PHY PRE PUR UNI", X-Powered-By=ASP.NET'.

Your SharePoint Admin Center is configured to 'Block Access' to applications that use legacy authentication:

1) Connect using "Web Browser Authentication" as a workaround. Note that, while Web Browser authentication might be an option for smaller migrations, it's not ideal for large unattended migration jobs. Your browser might prompt you to re-authenticate while your jobs are running, and at that point, your job will pause until you login again.

    OR

2) Connect using "Office 365 OAuth/Standard/ADFS Authentication", while Conditional Access is enabled to block Legacy Authentication for all accounts except migration accounts:

       Step 1) In SharePoint Online Admin Center, enable the 'Allow Access' to apps that don't use Modern Authentication:

      Step 2) Create  a Conditional Access Policy in the Azure Portal to block legacy authentication, with exception to the migration account(s) as explained in the attached document "SharePoint_Conditional_Access_Policy_Config.docx".