How can I resend a failed or rejected invoice with the same invoice number?

By Default the SAP Business Network does not allow you to use of duplicate invoice numbers, so you cannot resend invoices that are in Failed or Rejected status. you must use the new invoice number.

However, If you have any requirement where you want to use the existing invoice number, then you must contact your customer.

Customer can enable this by turning on the transaction rules Allow suppliers to reuse invoice numbers in the Default Transaction Rules section.

Once this rule is enabled, you will be able to reuse invoice numbers for invoices in Canceled, Failed, or Rejected statuses.

For more details about customer invoicing rule please check the link Allow suppliers to reuse invoice numbers.

You can check my customer's transaction rules in your account to see if your customer allows it.

SAP Business Network for Procurement & Supply Chain > Transaction Documents > Transaction (Invoicing)
SAP Business Network for Procurement & Supply Chain > Transaction Documents > Transaction Document Administration