Error connecting to web service API

The API works just fine in the desktop file, but when I upload it to PBIRS, I tested the connection for the source and an error pops up that says Unable To Connect To Remote Server. What's the issue here?

For reference, I'm following Reza Rad's post for this. I've mimicked Method 3 in this post. I also tried Method 3 Revisited (the XML method) but same error on PBIRS. http://radacad.com/solving-dax-time-zone-issue-in-power-bi

v-qiuyu-msft