Sound won't work when i take videos on snapchat

I have an iPhone 6s and when I try to take videos on snapchat, the sound is muffled even though access to my microphone is authorized both in my settings, and in the app. Sound works fine when I take videos with my normal camera or on Twitter and also work on Snapchat when headphones are in, but not without them. I've tried restarting my phone, deleting/reinstalling the app, and cleaning out my microphone with a needle.