My Lola has a cuddle cup as well! It’s literally her bestest friend (besides her humans of course!). After she pees in it – make sure you toss it in the washer or she is going to smell it and keep peeing! I used to throw Lo’s in alone on hot with some white vinegar.
I would second what bunnyfriend said about the hay/pellets. I even went as far to get a food bowl that attaches to the wire bars so she literally has no choice but to eat in her potty box and even though she is potty trained now it’s in her routine so I haven’t moved it out.
I don’t know how old your bun is but it was a lot of trial and error for awhile until Lola got it right. Lots of yellow puddles, messed up white fur, and stray poos. Before she is spayed it really is hit or miss with potty training – one day it works…the next there’s pee in the cuddle cup again!
The good news is – I feel like the cuddle cup is really going to be your best friend if you ever have to take your bun anywhere! I just stick it in her carrier and put her in there with is and she nuzzles down in there with it. It’s something that smells like her and I really do feel like it helps on the car rides! 
EDIT TO ADD: I read your profile and saw that she is ~7 years old and had a topic about enjoyable indoor living with rabbits….has she been spayed? Even if you don’t plan on getting another rabbit or having her anywhere she could possibly get pregnant, it really does make life easier once they are spayed. It’s like night and day and well worth the money if you take into account how much damage they can (/will) do damaging furniture and carpets by digging and peeing. After her spay, my bun no longer pees to mark every single place my boyfriend touches….SCORE!
And it does help potty habits 110%! If she is already spayed you can disregard but thought I’d just ramble on and let you know.