Slow loading of pfSense GUI when using cert and host override

I’d like some help in debugging a strange situation. When I load pfSense GUI using, it loads within a second or two, albeit not secured (no https). When I use the URL named in the cert, it takes over 3 minutes to load the GUI. Looking at Chrome “Development Tools:Network”, I see the pfblockerng taking up huge amounts of time (~ 15 seconds each). Any ideas as to what to explore and test?

pfSense 2.6
cert name “gonzo” by Let’s Encrypt
DNS Resolver host override for “gonzo” to

I never use LE Certs on the web admin interface so not something I have encountered, but my guess would be that your browser first doing an external DNS check and when that fails it does an internal.