Incoming Mails failing due to new Exchange Cert

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Now resolved

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The exact error when testing the email connection is as follows:     The request failed. The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel.

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We had to create a new exchange certificate and since then all incoming ermails are failing 

“The Underlying connection was closed: could not establish trust relationship for the SSL/TLS secure channel”.

I have an exported copy of the certificate and imported to the mobile print server but we still getting the same error. Do I need to install the certificate somehwere else?