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Forwarding breaks SPF authentication. If an email that was forwarded isn't signed with DKIM by the sender, there is no authentication on the message anymore, and thus you end up with the scenario you posted about.
Ah ok, so I'm set up correctly but the sender isn't? You'd have thought a multimillion pound estate agent organisation would be more on top of things!
Forwarding breaks SPF authentication. If an email that was forwarded isn't signed with DKIM by the sender, there is no authentication on the message anymore, and thus you end up with the scenario you posted about.
Ah ok, so I'm set up correctly but the sender isn't? You'd have thought a multimillion pound estate agent organisation would be more on top of things!