you should get a letter of explanation in about 2 weeks from the date the return was processed. it will have a phone number to call for more info. if you want to find out sooner, you'll have to call the IRS. best guess is that the IRS determine the dependent wasn't a qualifying individual for the HOH status.
Call 800-829-1040
1) Choose your language,
2) Then choose option 2
3) Then 1
4) Then 3
5) Then 2
6) When it asks you to enter your SSN or EIN do nothing – wait - - After it asks twice, you will get another menu
7) Then 2
😎 Then 3
It should then transfer you to an agent. Note when its phone line are busy you may be on hold for a long while or disconnected
if you want you can use this IRS website to check your filing status.
https://www.irs.gov/help/ita/what-is-my-filing-status
