My Pi 4 running 2 instances of Octoprint kept crashing until I switched to their official power supply. On previous models I always got away with whatever power supply I had around but the 4 doesn't play around when it comes to power consumption.
I've had various Pi models over the years starting with the original and I've never gotten a power supply with it. You must have bought a bundle deal, which could mean a good or bad one depending on the seller..
I had to replace the one mine came with. It was new-ish, so I was able to get it for free under warranty, but be aware- quality control for their power supplies is not great (at least as of ~2017)
My Pi 4 running 2 instances of Octoprint kept crashing until I switched to their official power supply. On previous models I always got away with whatever power supply I had around but the 4 doesn't play around when it comes to power consumption.