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jonmovaci's avatar
jonmovaci
Copper Contributor
Sep 25, 2025

Exchange Hybrid Migration Endpoint cannot be created

 

We cannot create an Exchange hybrid migration endpoint using remote server and the error when we create bypass verification is

 

 

Error: CommunicationErrorTransientException: The call to 'https://mail.foxvalleyfire.com/EWS/mrsproxy.svc' failed. Error details: The HTTP request was forbidden with client authentication scheme 'Negotiate'.. --> The HTTP request was forbidden with client authentication scheme 'Negotiate'.

 

 

 

 

We have check on Exchange on prem server and found that the MRSproxy has turned on. What do we need to check from on premise? Please refer to below for the error

 

 

 

 

 

 

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2 Replies

  • net_tech's avatar
    net_tech
    Copper Contributor
    Feb 06, 2026

    Hi,

    Where you able to resolve the issue ?

    We are also facing the same error moving from EX2019 CU15 to O365.

    • Scott_Schnoll's avatar
      Scott_Schnoll
      Brass Contributor
      Feb 09, 2026

      jonmovaci​ 

      Verify that MRS Proxy is enabled:

      Get-WebServicesVirtualDirectory | FL Identity,MRSProxyEnabled

      If the output is false, then run:

      Set-WebServicesVirtualDirectory -Identity "EWS (Default Web Site)" -MRSProxyEnabled $true

      iisreset


      Also check authentication settings on your EWS virtual directory.  Enable Basic auth and disable Windows auth and do another iisreset.

      Then, re-run the HCW and try again.

      If none of this helps, please share the output of the following:

      Get-WebServicesVirtualDirectory | FL Identity,MRSProxyEnabled,BasicAuthentication,WindowsAuthentication

       

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