Now this is weird...
I did some experimenting. First I tried adding the website to the Bitdefender Whitelist. I still had the problem. I removed it from the Whitelist and then disabled SSL scanning. No surprise...the website loaded with no problems. I re-enabled SSL scanning, and the website still came up with no problems.
I went back in to Bitdefender to make sure I had re-enabled SSL scanning. And, yes it was enabled. Just to be sure, I shut down the PC and restarted it. I checked Bitdefender and it shows SSL scanning is enabled. The website loaded with no problem.
Somehow, it appears that disabling and then re-enabling SSL scanning has solved the problem. It's a mystery to me, but I'm happy that the problem is gone...