When rendering email messages, by default the API uses the English language to render field labels such as From, To, Subject etc. There might be the case when you want to change the label of the fields in email message’s header. GroupDocs.Viewer Cloud is flexible enough to allow you to use the custom field labels for email header. The API provides a new property FieldLabels in EmailOptions class to change the field labels....Please get your Client Id and Client Secret from https://dashboard...place Client Id in "client_id" and Client Secret in "client_secret"...