It’s possible that a submission is still pending. This means that your co-submitter has not yet fully completed their account.
If you click on the submission, you can resend the invitation to your co-submitter. Once the co-submitter is linked, this message will disappear and your submission will be placed.
Has the co-submitter already used the invitation but the message remains?
In that case, the co-submitter still needs to confirm the household. They have received an email for this. Once they accept the household in that email, the submission will be placed.