Has anyone encountered before?

Scenario

Exchange environment is Exchange 2016 & Exchange 2019.Exchange 2016 – Extended Protection not enabledExchange 2019 – Extended Protection enabled.User mailbox is residing in Exchange 2019 User attempt to login via OWA (FBA) on Exchange 2016 When login, the page keeps looping back to the logon screen.

Error in httproxy owa logs: WebExceptionStatus=ProtocolError;ResponseStatusCode=401;WebException=System.Net.WebException: The remote server returned an error: (401) Unauthorized.

Attempted to login to both OWA & ECP via OWA on Exchange 2019 – successful.

​Has anyone encountered before?ScenarioExchange environment is Exchange 2016 & Exchange 2019.Exchange 2016 – Extended Protection not enabledExchange 2019 – Extended Protection enabled.User mailbox is residing in Exchange 2019 User attempt to login via OWA (FBA) on Exchange 2016 When login, the page keeps looping back to the logon screen.Error in httproxy owa logs: WebExceptionStatus=ProtocolError;ResponseStatusCode=401;WebException=System.Net.WebException: The remote server returned an error: (401) Unauthorized. Attempted to login to both OWA & ECP via OWA on Exchange 2019 – successful.   Read More

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