This message is not related to the linking of the application but to the account access. As you said, you created a new account so this is not the issue. You have to link your application to your new account.
It's unclear what do you mean. Your partner application and your application are two different applications or you refer to a single application where one of you is sponsor and another is primary applicant (PA). If later, you you have to link the application using PA information only. You can't link using sponsor's data.
If you are talking about two unrelated applications - then you need to provide more information about your application.
What kind of application, when submitted, what communication have you received already etc.