Due to a goof up on my part in my test lab, I was encountering this error. Found this forum post which helped me fix it; after which I realized the error was happening coz of a configuration error on my part. No point going into what my mistake was (in short – I have two servers that act as both StoreFront and Delivery Controller; the base URL of the StoreFront is one of the servers but I was also trying to access the StoreFront via the other and it worked but kept erroring (it worked coz the IIS website is there; and it errored coz I am not supposed to access it via that URL) so that was me being silly).
Thank you Internet!
Time to setup NetScalers in my test environment so I can access the StoreFront via them. Which is what I should have done in the first place to load balance between these two servers.