CP301 is sent to verify that you’ve registered for an IRS online service.
If you haven’t, you need to immediately call the number on the notice to disable your account. See Understanding Your CP301 Notice for more information.
Typically, when the IRS suspects that a tax return with your name on it may be the result of identity theft, the agency will send you a special letter, called a 5071C Letter.
Please see the TurboTax article Tips for Handling Identity Verification Requests From the IRS for more information.
