Power issues.. Full day then suddenly resolved

Hi, my son's Xbox One S wouldn't turn on yesterday evening. If he pushed the power button it would either beep and that's it or the power button would light up but wouldn't stay on very long. If he pushed the eject button it would beep too. It would also try to power on when he did that. (there was no CD inside)

We unplugged the power cord. Waited more than 10 sec and tried again. Tried so many times it's crazy and nothing was helping. This morning I tried again and so did he. Well after we had a busy day we came home and suddenly it's working. I'm very confused. Happy but nervous.