I am using the IP Address, correct logins, but can't connect this SQL Server instance to the Gateway. I made a success connection on the Gateway server using SSMS. I pinged the server name successfully using cmd line. What else should I look as?
Error
Unable to create connection for the following reason: Logging into Sql server failed. Possible reasons for this error include an invalid authentication mode, a missing login in Sql server, a login from an untrusted domain or a problem contacting the domain controller for the authentication request.