First of all, I highly recommend you to keep the Sound Alarm (at least 5 seconds) — technically there should be a mandatory 15-second sound alarm for all automated garage door openers — when someone controls the door remotely, it’s potentially dangerous (or at least surprising to the person at the garage) to observe the door suddenly closing itself without any audible warning.
Second, I can’t reproduce the issue you reported — I disabled alarm and use Blynk app and it works just fine. Note that the Blynk button is set to ‘Push’ mode, which means you have to press it for at least half a second before releasing it. If you click it too quickly the controller won’t respond to it. Press it down and then release it should work.