We are testing an add-in for Excel that has a form that is POSTed to https://httpbin.org/anything. The form will not POST in Excel 2016 version 15.39 (171010) for Mac (High
Please refer this post for latest on this. Seems to be a duplicate issue.
Update Excel 2016 on Mac to version 16.9.0 (18011602). We are able to POST from Excel 2016 for Mac! Thanks to the entire MS team.