I need to step back and speak about this at a higher level.
The other calls work, only the VRP call fails. So for instance, I can generate a token and use that token to call a single-route optimization. However, when I try the VRP call, I get the 498 Invalid Token. So it's not as if I have an invalid token in reality since that same token works for other calls.
I'm not sure of the best forum area in which to seek help. I tried the 'ArcGIS Online' forum and they told me to seek a developer forum, which is why I'm here. But really it's an authentication issue, not so much language specific probably. Is this the correct place for me to have posted or is there a better place to re-post again?