Per IRS Instructions for Form 2441 Child and Dependent Care Expenses, on page 4:

CAUTION! You must reduce your earned income by any loss from self-employment.

This refers to the amount of earned income reported for the taxpayer and spouse on Lines 4 and 5 of Form 2441. Due to these instructions, the taxpayer (or spouse on a joint return) must reduce his/her individual income by the amount of their self-employment loss. This may result in the return not being eligible for the credit as both must have earned income as explained on page 2 of the instructions:

Who Can Take the Credit or Exclude Dependent Care Benefits?

You can take the credit or the exclusion if all five of the following apply.

1. Your filing status may be single, head of household, qualifying widow(er) with dependent child, or married filing jointly. If your filing status is married filing separately, see Married Persons Filing Separately, later.
2. The care was provided so you (and your spouse if filing jointly) could work or look for work. However, if you didn't find a job and have no earned income for the year, you can't take the credit or the exclusion. But if you or your spouse was a full-time student or disabled, see the instructions for lines 4 and 5, later.
3. The care must be for one or more qualifying persons.
4. The person who provided the care wasn't your spouse, the parent of your qualifying child, or a person whom you can claim as a dependent. If your child provided the care, he or she must have been age 19 or older by the end of 2020, and he or she can't be your dependent.
5. You report the required information about the care provider on line 1 and, if taking the credit, the information about the qualifying person on line 2.

Note that any link in the information above is updated each year automatically and will take you to the most recent version of the document at the time it is accessed.