We are attempting to use MS Graph as well to use the Mail v1 API. We have recently had some luck using Azure AD to authenticate and get access tokens using the v1 auth/token endpoints and accessing O365 Online Exchange API v1 in BP, however MS is planning to deprecate basic auth from v1 on 11/1/18 and then fully decommission v1 on 11/1/19. Thus, we would like to MS Graph going forward. We have successfully modelled the requests for Graph and Mail API in Postman however we are not having much luck making it work in BP.
