Safari Can't Open the Page (Persistent Certificates Problem in Safari)

I'm getting the error message "Safari can't open the page because Safari can't establish a secure connection to the server." Yet the page runs perfectly on an iPad and other computers. I suspect a problem with Keychain/certificates but I can't pinpoint the problem. Any ideas?

Running macOS 10.12.1, and system date/time is correct.

Solution 1:

I ended up solving this issue on my machine by following these instructions which seem to be different for 10.12 vs. prior versions of OS X. To summarize:

OS X 10.12

sqlite3 ~/Library/Keychains/*/ocspcache.sqlite3 'DELETE FROM ocsp;'

For OS X 10.11 and earlier

sudo rm /var/db/crls/*cache.db