Taxes letter from irs

So I received a letter from irs that they are viewing my accuracy on my taxes and below states that they are looking into income, tax credits, income withholding and business, I don't have a business, I reviewed my return multiple times and just now again and do not see any errors under any of this, it just says to wait up to 60 day before they may send it, I've never had this happen before. But the return was accepted just hours after submitting it.