Hi,
Migrating from single 2010 server to 2x 2013 servers in prod and 1x 2013 in DR with a DAG cluster. I haven't begun migrating user mailboxes over yet. Mail is flowing through 365 to 2010 presently.
When running a health report on any 2013 server, I get an unhealthy FrontendTransport error. I suspect this is related to the following event log entries:
Application / MSExchangeTransport
EventID 1025
SMTP rejected a (P1) mail from 'HealthMailbox7730f2644a204d348de7f46d199b7df5@domain.local' with 'Client Proxy EX01' connector and the user authenticated as 'HealthMailbox7730f2644a204d348de7f46d199b7df5'. The Active Directory lookup for the sender address returned validation errors. Microsoft.Exchange.Data.ProviderError
Does anyone have an idea whats causing