The Mailbox Replication Service was unable to connect to the remote server using the credentials provided. Please check the credentials and try again. The call to 'https://webmail.blah.com/EWS/mrsproxy.svc' failed.
Error details: The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM'. --> The remote server returned an error:
(401) Unauthorized.. --> The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM'. --> The remote server returned an
error: (401) Unauthorized.
    + CategoryInfo          : NotSpecified: (:) [New-MoveRequest], RemotePermanentException
    +9,Microsoft.Exchange.Man
   agement.Migration.MailboxReplication.MoveRequest.NewMoveRequest
    + PSComputerName        : outlook.office365.com

UserName1 : <domain><SamAccountName>

UserName2 : <SamAccountName>

UserName3 : UPN

RunspaceId         : 3966b356-0f49-46c3-9373-e914827fc6ed
Result             : Success
Message            :
ConnectionSettings : <ExchangeConnectionSettings HasAdminPrivilege="True" HasAutodiscovery="False" HasMrsProxy="True" AutodiscoverUrl="" IncomingEmailAddress="" IncomingRPCProxyServer="webmail.blah.ccom"
                     IncomingExchangeServer="webmail.blah.com" IncomingNSPIServer="" IncomingDomain="" IncomingUserName="UserName<#>" EncryptedIncomingPassword="something"
                     IncomingAuthentication="Basic" ServerVersion="" TargetDomainName="" SourceMailboxLegDn="" PublicFolderDatabaseServerLegacyDN="" IsPublicFolderMailboxesMigrationSource="False" />
SupportsCutover    : False
ErrorDetail        :
IsValid            : True
Identity           :
ObjectState        : New

RunspaceId         : 3966b356-0f49-46c3-9373-e914827fc6ed
Result             : Failed
Message            : The connection to the server 'webmail.blah.com' could not be completed.
ConnectionSettings :
SupportsCutover    : False
ErrorDetail        : Microsoft.Exchange.Migration.MigrationServerConnectionFailedException: The connection to the server 'webmail.blah.com' could not be completed. --->
                     Microsoft.Exchange.MailboxReplicationService.RemotePermanentException: The Mailbox Replication Service was unable to connect to the remote server using the credentials provided. Please check
                     the credentials and try again. The call to 'https://webmail.blah.com/EWS/mrsproxy.svc' failed. Error details: The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The
                     authentication header received from the server was 'Negotiate,NTLM'. --> The remote server returned an error: (401) Unauthorized.. --> The HTTP request is unauthorized with client
                     authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM'. --> The remote server returned an error: (401) Unauthorized. --->
                     Microsoft.Exchange.MailboxReplicationService.RemotePermanentException: The call to 'https://webmail.blah.com/EWS/mrsproxy.svc' failed. Error details: The HTTP request is unauthorized with client
                     authentication scheme 'Negotiate'. The authentication header received from the server was 'Negotiate,NTLM'. --> The remote server returned an error: (401) Unauthorized.. --->
                     Microsoft.Exchange.MailboxReplicationService.RemotePermanentException: The HTTP request is unauthorized with client authentication scheme 'Negotiate'. The authentication header received from
                     the server was 'Negotiate,NTLM'. ---> Microsoft.Exchange.MailboxReplicationService.RemotePermanentException: The remote server returned an error: (401) Unauthorized.
                        --- End of inner exception stack trace ---
                        --- End of inner exception stack trace ---
                        --- End of inner exception stack trace ---
                        at Microsoft.Exchange.MailboxReplicationService.MailboxReplicationServiceFault.<>c__DisplayClass97_0.<ReconstructAndThrow>b__0()
                        at Microsoft.Exchange.MailboxReplicationService.ExecutionContext.Execute(Action operation)
                        at Microsoft.Exchange.MailboxReplicationService.MailboxReplicationServiceFault.ReconstructAndThrow(String serverName, VersionInformation serverVersion)
                        at Microsoft.Exchange.MailboxReplicationService.WcfClientWithFaultHandling`2.<>c__DisplayClass7_0.<CallService>b__0()
                        at Microsoft.Exchange.Net.WcfClientBase`1.CallService(Action serviceCall, String context)
                        at Microsoft.Exchange.MailboxReplicationService.WcfClientWithFaultHandling`2.CallService(Action serviceCall, String context)
                        at Microsoft.Exchange.Migration.MigrationExchangeProxyRpcClient.CanConnectToMrsProxy(Fqdn serverName, Guid mbxGuid, NetworkCredential credentials, LocalizedException& error)
                        --- End of inner exception stack trace ---
                        at Microsoft.Exchange.Migration.DataAccessLayer.ExchangeRemoteMoveEndpoint.VerifyConnectivity()
                        at Microsoft.Exchange.Management.Migration.MigrationService.Endpoint.TestMigrationServerAvailability.InternalProcessEndpoint(Boolean fromAutoDiscover)
IsValid            : True
Identity           :
ObjectState        : New