I powered 'off' my Huawei Y6 last night and this morning it won't turn on
I had this problem and it's persistent but I figured out the solution so for everyone else dealing with this, what you do is fiddle with it until you see a battery symbol or a flashing red dot on the phone. When this happens, leave it and make sure it doesn't stop flashing. If successful it'll eventually go to yellow, then green, then your phone will turn back on. If not, try charging it with different cables and different usb ports/adapters while taking the battery out and putting it back in to try and get it to work. It's annoying and very counter intuitive.