With all due respect sir, that has all been covered above already. If you have not yet read through the entire thread please feel free to review it more thoroughly to better understand.
This has nothing to do with cache, cookies, browsers, OS or extensions. As JB1887 posted above there is some relatively damning evidence pointing to a potential issue with the website itself being "blacklisted" (aka blocked/inaccessible) by an industry-standard filtering service known as Barracuda.
I ran a quick test here myself which indeed confirmed what JB1887 had suspected: https://mxtoolbox.com/SuperTool.aspx...2&run=toolpage
I will defer to him and any others from here on out. The issue(s) at this point are likely well beyond the scope or reach of any end user.
If it does not quite make sense to you at this point it seems it would be prudent to continue to escalate the issue internally until it reaches someone who can address it more directly.
I certainly do not have any answers or explanations for it myself (just a random dude on the internet) and cannot practically invest any more time in the matter. I am but a speck of dust in the greater universe.
(Although admittedly the Borla on my 2017 5MT DK at full throttle occasionally *does* give me an exaggerated sense of self-importance!) Haha.
Thank you again to everyone for your help and best wishes!!