Soap API should include to check WSDL url in account services profile if incorrect account name error shown.
The WSDL url is dynamic, so the API you are calling against may not match the API in your web services profile. When calling against an incorrect WSDL url, only "Incorrect account name." message is given, even if credentials are correct. It may be helpful to add, "Please double check the WSDL URL in your account profile as well as your account name, profile name and password."