Thank you for your reply. Yes it is StandAlone SMS / GW with HTTPS inspection enabled. Cpview looked okay from what I could tell.
Browsing office.com as my testing I noticed the bellow observations, the left image is with HTTPS inspection, the right is without.
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
The custom HTTPS bypass rule does not appear to be working, I have added portal.office.com and office.com and it still inspects them. The financial services rule is working in that I could connect to banking sites with no issue.
I tried a local news website, and it connects fine, the certificate shows issued by and the name of the HTTPS inspection certificate "client.com"
I observe the following log in the Man Server:
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I have had a look at sk159872, which doesn't seem to give me any help, I updated the Trusted CA list on the smartdashboard with Checkpoint support yesterday. I have added the https inspection certificate to this list and it has not helped. I have observed a fair number of Microsoft URL's failing with Untrusted Certificate.
I am waiting for more feedback from Checkpoint as to what to check next.