Why is it difficult for foreigners to find a studio apartment in Hongdae?

I'm currently looking for a studio apartment in Hongdae, but I've been rejected multiple times because I'm a foreigner. What could be the main reasons for this happening? I'm curious if others have had similar experiences. Whenever I try to find a studio apartment, the process becomes difficult due to being a foreigner. Often, the deposit or monthly rent conditions suddenly change, or I'm told that the contract is impossible altogether. I would appreciate any advice on how to handle such situations. Are there any ways for foreigners to easily find studio apartments in the Hongdae area, or any recommended real estate agencies? I'd like to hear the opinions of those who have experience in this matter.