Cannot Connect to SQL Server from Looker

Cannot connect to a publicly available SQL Server from Looker.  I can connect to MS SQL Server from local SSMS client  using my credentials but when try to connect from Looker, get the following error:

Developer Tools:
POST https://lookerstudio.google.com/u/2/getAccountTree 503 (Service Unavailable)

Sorry, we encountered an error and were unable to complete your request.

 

Error ID: c41f6bc3

Any help will be greatly appreciated

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