CP75 and CP75A notices are requests for additional proof that you qualify for a credit you claimed on your tax return. This is a tax audit.
Notices and Forms You May Receive
You will receive either IRS Notice CP75 or IRS Notice CP75A plus a separate form or forms to respond to the specific issue the IRS is auditing.
Receiving a notice does not mean you weren’t eligible to claim a tax credit. You may have made a mistake when filing your tax return that you can easily fix.