iPhone 11 mute switch not working

Hi

I had a cracked iphone 11 and the frame got bent a lot. I ordered a new back housing. I took all the parts from the broken iphone to the new casing except the mute&volume flex since it got ripped when the iphone broke. So I ordered a new flex and installed it on the new back housing. I put on the mute button under the springs. For some reason the mute switch does not work. The volume buttons work perfectly. I dont understand why since mute switch and volume buttons are connected on the same flex. I tried to check the ribbon that goes from the mute switch if it has any damage but I dont see anything wrong. Can it be the button itself is not seated correctly under the springs?