Next I would try doing NSLOOKUP and see what IP address that site is resolving to from your DNS. It's resolving to
50.116.60.143 and working properly with https for me. You can also play with this from the Meraki dashboard, under appliance status and, clicking on the Tools button and using DNS Lookup.
After that, you may want to check your firewall flows and do some packet captures to see if traffic is going to the correct IP. You need to export to a syslog server to see flows on an MX. Good luck!