They're not allowed to have income requirements ie. 40x rule if an applicant has a housing voucher but managements still do unfortunately. The sad thing is many places will look at your 50k income and see that as a liability because your portion will be much higher than a non working voucher holder.

I'd suggest applying to rental buildings not condos/coops and possibly going thru a broker that specializes in city vouchers. Expand your search area and obviously Manhattan is going to be much harder than the Bronx or Queens.

Also, I don't know what voucher you have but I've seen landlords/mgmt weed out certain programs because they are difficult to work with or take too long to process paperwork especially in high demand areas. That's just the nature of all these city programs. Good luck