@Lcunnin1 - most likely, the issue has to do with the Recovery Rebate Credit or the Child Tax Credit.  If you answer the following I can probablt help you understand what happened>

1) what is on Line 28 of Form 1040?

2) what is on Line 30 of Form 1040?

3) what is the EXACT amount of the IRS adjustment? Please confirm it was $6221. 

I am going to bet this relates to your children and the Child Tax Credit

4) what is the age of each child as of 12/31/21?

5) what is on line 14f for Form 8812?

I think i can help.

Hi! Line 28 is blank as I don’t have any children and line 30 states 1400$

@Lcunnin1 okay - a few more questions

1) how many people listed on your tax return? just yourself or a spouse?

2) did you receive the 3rd stimulus payment last March - May, 2021? Please review your bank statements from that time frame.

3) what is on Line 35a and 36 of Form 1040?  You stated you were expecting $9922 and that should be on Line 35a; Line 36 should be zero. 

4) Look on your transcrips at IRS,com and confirm that you see a payment for only $3701.

worst case: the IRS is sending a letter that will explain what they did, 

The problem with the IRS letter is it is confusing and does not state the actual problem in your situation.

Only a list of possible reasons.