IRS ID verification address for an apartment

Hi, I got a 5071C letter and I'm trying to get my stimulus check. I need to verify my identity on the IRS website but I don't know how they want me to put in my address since I live in an apartment. I've tried so many combinations of my address that I don't know what to do anymore. I've also tried calling the number they gave on the letter an unreasonable amount of times for 3 days straight now and it always tells me they are too full. It's like the IRS is trying to completely block me from getting this money I need! Can someone please explain how I'm supposed to input my address into the ID verification website?