Suilend: Can't borrow deposited asset

Hey, quick question for anyone familiar with Suilend.

I've deposited some sSUI on Suilend, which gives me a borrow limit of 270 USD.

Thinking about borrowing some DEEP, but when I click on DEEP and switch to the "Borrow" tab, it tells me: Can't borrow deposited asset

This confuses me quite a bit. I thought borrow means that I am borrowing, not lending, the asset. Why do I need to hold DEEP in my wallet to borrow more DEEP? Isn't my sSUI, which is also responsible for raising my borrow limit in the first place, acting as the collateral?

I am thanking you kindly in advance for providing your insights!