Hello! Anyone using EUFY S1 pro breast pump? I must do something wrong. First time use was normal and then not one drop of milk coming out. Thank you 
sid you figure out your issue? this has happened to me before and my issue was that i had the diaphragm in backwards
I’ve been using mine for a couple weeks. That’s happened to me when I’ve missed my nipple, which is surprisingly easy to do with the S1. Just a tiny misalignment and you get nothing.
Flange inserts, proper assembly, nipple placement
I would check your diaphragm is in the right way I have accidentally put it in backwards before. If it is I would also check your duckbill. If it’s not holding suction that could be the issue.
Check your nipple placement. Lean forward to put them on versus lifting your breast up really high to put them in.