We’re just renewing the SSL certificate for verygoodemail.com
This will be rolled out onto the Zimbra servers on Monday evening (10/07).
Based on our recent experience with renewing apm-internet.net certificate, any partners using their own domain and pointing at a Zimbra server might have issues with iPhone users and SSL.
There are only two possible solutions to this.
1) Change the config to point at verygoodemail.com instead of your own domain, and
2) De-configure and re-configure the mail client on the iPhone.
Apologies for any inconvenience that may be caused by this Apple bug.