Hi, Gary. Your browser, tracert and ping are also other apps - all still on the same computer that is having the connection problem. MSFS2020, DCS, Steam, etc. are not connecting to VoiceAttack.com (at least I hope not). That means something on your machine is blocking VoiceAttack.com, or you are not able to resolve the address of VoiceAttack.com on that computer. As you had indicated, you have one machine that is not able to connect, and another machine that can. I am running on ipv6 and am able to connect without issue (this includes the registration- and there are no reports of anyone else having issues with connecting. A nifty tool to try (not just for VA, but for any site you may have trouble connecting to) is
https://downforeveryoneorjustme.com/voiceattack.comor
https://shotsherpa.com/ (put voiceattack.com in the search bar)
When you ping VoiceAttack.com, what are the results? If you get an attempt at IP address 192.185.7.212, that means that DNS is working. If it does not resolve to that address, you have a DNS problem (that means that your DNS server is not able to xref VoiceAttack.com to that IP address). If it does resolve to that address, but cannot connect, you've got something on your machine that is blocking access (internet security package, firewall). Outside of that, there is basically nothing that can be done from the VoiceAttack.com side, as the site is working as expected/intended with no recent updates. I'm not sure where to guide you next from the local machine side - hoping another user may chime in with some useful tips to try out.
Another long shot, but perhaps there is an entry in your hosts file for VoiceAttack.com?