It's the so-called "travel rule" which took effect recently. You can either make something up, or select that it's your own wallet (which it kinda is, but it might not work if they want to verify that you can send from it), or do it the "legit" way and download something like [
electroncash.org]
Electron Cash to your smartphone then temporarily send it there first.
(I wouldn't recommend using a software wallet on your PC, or storing large amounts on a smartphone wallet, due to the malware risk. But smartphone wallets are usually fine for smaller amounts.)