Just like all stale dated checks you must request a new one ...
If you received your payment by check and it was lost, stolen or destroyed, you should request a payment trace so the IRS can determine if your payment was cashed. See How do I request a payment trace to track my first or second Economic Impact Payments?
If a trace is initiated and the IRS determines that the check wasn’t cashed, the IRS will credit your account for that payment but the IRS cannot reissue your payment. Instead, you will need to claim the 2020 Recovery Rebate Credit on your 2020 tax return if eligible.
Note: If you are filing your 2020 tax return before your trace is complete, do not include the payment amount on line 16 or 19 of the Recovery Rebate Credit Worksheet. If you do, you may receive a notice saying your 2020 Recovery Rebate Credit was changed, but an adjustment will be made after the trace is complete and it is determined your payment has not been cashed. You will not need to take any additional action to receive the credit.
If you were issued a payment and have not received it at all, see How do I request a payment trace to track my first or second Economic Impact Payments?
https://www.irs.gov/coronavirus/second-eip-faqs
