maybe you have china phone version and not global LTE version?they have different networks.you can try instlal china version.but it doesnt have play store.you will have to root and it can cause bugs again..you did "erase all data" before installing in boot menu?
there is no official ROM with norwegian language. you using custom made/modified ROM.thats why you have bugs/problems .better install official ROM and use english.
it seems they still have only china official ROM for mi 4 :/ http://en.miui.com/download-240.html that means no play store...