What this IRS notice code means, and what to check before you reply.
Start with these steps before you reply.
Read the notice carefully and note any deadline. Gather returns, notices, and payment records. Book a free strategy session before responding if the amount is large, unclear, or collection language appears.
We disallowed your treaty exemption because you didn’t reply to our request for more information. We have changed your tax return accordingly.
406 is in our IR Manual catalog. Official wording is dense — we translate it for business owners and individuals and map realistic next steps.
Every notice in this library, sorted the way the IRS numbers them.