Why aren’t egg whites not whipping past medium peaks?

Hi! I’ve been making macarons for a while now and I’ve had very successful batches. I’m trying lemon macarons today but my egg whites are not whipping past medium peaks. I did not over whip them, as I’ve been paying close attention. This is my second time whipping today, and I wiped down the bowl about 3 times with vinegar before my second batch but they’re still not whipping well. I have lemon extract in here, could it be that? Google said no but I’m beginning to believe the lemon extract is causing this.
Thank you!