Your latest certificate which is currently in use is only valid for jimmymackhealing.com. But because you have a redirect to www.jimmymackhealing.com in place, everybody will get a certificate error.
Just want to be very clear about where the issue lies. I've seen people here on the community persevere in inadequate assumptions, which would delay the right action.
Wouldn't you rather have one certificate with both hostnames? The site you're using does allow you to input multiple hostnames at the same time by separating them with a comma it seems.
I'm REALLY hoping that you submitted your own certificate signing request (CSR). If their website generated it for you internally then they also generated the private key that goes with it, which means that your website would then have no security.
That's an exaggeration. It means that the operator of the shieldsigned site (or somebody else with access to their server infrastructure) could have maliciously kept a copy of the private key and would then be able to use it to intercept communications to the jimmymackhealing site if they were also in the right place on the network to do so or could somehow tamper with its DNS records.