There is not a big issue but the arrangement of lesson content flow in module [ Interfacing sensor over VPS ] is slightly different.
This lesson [ Project 10: Sending an Email when Temperature Crosses Threshold ] is arranged before this lesson [ Introduction to Mailgun ] in the module.
Technically [ Introduction to Mailgun ] should come first then this lesson [ Project 10: Sending an Email when Temperature Crosses Threshold ].
Thanks
Nakul Dubey