[MeshKit Error] ErrHTTPPostRequest needs improvement

[leecalcote]

          ErrHTTPPostRequest - the message isn't overly accurate or helpful. It would seem that the most likely cause of this failure is

1. User's network connectivity. Can they reach the currently configured remote provider?
2. The currently configured remote provider is unavailable / down.
3. Network connectivity is fine, but their request was malformed. Are they missing a required parameter (an email address) or did they provide an invalid email address?
4. Network connectivity is fine, but they authentication failed.

Originally posted by @leecalcote in #33 (comment)