Supplier user is getting error while creating Non-PO invoice in Supplier Portal

Hi team,
Supplier user is getting an error when creating Non-PO invoice in Supplier portal, where user enters wrong email address in requester email address field 3 times. Error: 'You've made 3 attempts to enter a valid requester's email address. You must enter the invoice again'.
How to avoid this error? Because sometimes Supplier is not aware of exact email address of requester. Kindly support to get a solution