I am using Umbraco version 7.5.4 and courier version is v3.0.5. I have two environment Dev and Live. Dev environment using MSSQL for database and Live environment using MySQL.

I have purchased license to transfer content between those domains (Dev and staging). I would like to transfer content from Dev to staging but when I tried to transfer content it throw an error:

System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> System.ArgumentException: No User exists with ID -1 at umbraco.BusinessLogic.User.SetupUser(Int32 ID) at umbraco.BusinessLogic.User..ctor(String Login) at Umbraco.Courier.RepositoryProviders.WebserviceProvider.Security.SecurityHelper.ValidateUser(String login, String password) at Umbraco.Courier.RepositoryProviders.WebserviceProvider.Security.Authentication.AuthorizeByCredentials(String login, String password, Boolean cacheAuthResult) at Umbraco.Courier.RepositoryProviders.Webservices.Repository.AuthorizeByCredentials(String username, String password) at Umbraco.Courier.RepositoryProviders.Webservices.Repository.Authorize() at Umbraco.Courier.RepositoryProviders.Webservices.Repository.CloseSession(String sessionKey) 
--- End of inner exception stack trace ---

If I try to transfer content between MSSQL to MSSQL (local to dev) environment then its working fine