Domain Mapping, SSL, and Cloudflare

I know this is a fairly common issue and I have found other threads that address very similar problems to mine, like:

https://premium.wpmudev.org/forums/topic/domain-mapping-ssl-and-cloudflare

and

https://premium.wpmudev.org/forums/topic/how-to-setup-ssl-for-mapped-domains#post-803587

but they don’t seem to address the specific issue I’m having, which is this:

I had a custom domain successfully mapped to a subsite on my network. I routed my main site through Cloudflare, and this too was successful, in that nothing broke and the main site at least was receiving CF benefits. I was happy with that.

Then I moved servers.

Now, mapping the custom domain to the new server causes first a security warning, then a redirect loop error.

I have a cert for the main domain and also a wildcard cert installed on the new server. The main site and all subsites seem to be running fine, after altering the htaccess file to force https yesterday for all sites (https was working, http was not). I have a dedicated IP on the new server. The domain mapping plugin (WPMU’s) seems to have detected that successfully and that was actually auto-entered into the IP field when I looked at it.

But changing the A record to the new dedicated IP at the registrar of the custom domain causes the aforementioned errors.

What should I be doing in order to successfully map this custom domain to the new server when the dedicated IP is routed through Cloudflare?