iMessage and Facetime not activating on iPhone 6 plus

I bought an iPhone 6 plus for parts and I changed the motherboard. Everything works except iMessage and Facetime which when I try to activate them it says there was an error activating facetime and iMessage. I checked time zone, my number in settings and I have 18 sms left but with 0,01€ balance on my card. What can I do?