If the name of your US-based business was recently updated with the IRS (e.g. within the last 3 months), or if you are a new business registering for the first time, the IRS might not have updated their database with your new details yet. This can take the IRS 3-4 weeks on average.
If your legal name and tax ID on file match the info on your SS-4 confirmation letter (for new TINs issued within the last ~3 months) and Stripe is unable to verify it with IRS records, upload a copy of your letter to the Dashboard. You can also contact Stripe Support for further assistance.