Is it maybe IRS form 15111?
IRS Letter 15111https://www.irs.gov/pub/irs-pdf/f15111.pdf
CP 09 is the IRS Notice that issues the form 15111. Use the link below to the CP 09https://www.irs.gov/individuals/understanding-your-cp09-notice
And see this post for more info especially page 4https://ttlc.intuit.com/community/after-you-file/discussion/anyone-else-need-help-with-finding-the-f...
