Use 'Follow Stream' 'TCP' in the Conversations dialog to display that conversation. Dismiss the 'raw data' display that pops up; we won't need that for what we're doing. "Analyze\Follow\TCP Stream"
Highlight the 'Certificate' packet in the top pane of the display in the Info column.
Review the Transport Layer Security section and look for highlighted data, if it is highlighted it means there is an error you can drill into.
To see the signer of the Certificate drill down into Transport Layer Security \Handshake Protocol\Certificates\Certificate:...\signedCertificate\Issuer
Review the content for the RDNSequence to see if it matches expectations.
CBC Sites
Certs
Cert URL's
Prod
GoDaddy
http://ocsp.godaddy.com http://crl.godaddy.com
Updates
DigiCert
http://crl3.digicert.com http://crl4.digicert.com
Additional Information
Firewalls and proxies can both do SSL Inspection, when a device intercepts our packet and provides its own it may interfere with the validation of or product, manifest or signature files.