If an invoice is in “Declined” status, this means the invoice has been reviewed by the invoice reviewer. This state indicates there is an issue with the invoice you submitted and it will not be processed until it is resubmitted. When an invoice is declined you will receive an email notification at the email entered in your user settings.
Don't worry! In these cases you will most likely be contacted by your invoice reviewer via email or phone.
The invoice decline reason at the top of the Invoice Detail page