Denied applicant based on income - now they say they have a housing voucher

[Katarina Takahashi]

This is my first time as a landlord screening applicants.

I had an applicant on Zillow for a property with an income less than the rent amount. I confirmed with them their income amount. After they confirmed they make less than the rent, I denied the application on those grounds.

After that, they messaged me that they have a housing voucher which was not included in the application as a source of income and that the housing voucher would make their income reach the minimum requirements.

What do I do now? Tell them to re-apply, since their application has already been denied? I don't want to discriminate and I know it's important to be fair and take into account all income sources such as housing vouchers. 

Thank you in advance for any advice.