Nostalrius Begins - Quality wow vanilla realm (1.12)

hi my friend borgs was playing wow nostalruis with me and she cant play because her ping is too high she can play vanilla wow fine but not nostalruis fine she cant loot or do anything because she has a high ping i use the same internet and i can play fine the internet was restarted i turned off all internet devices and my friend couldnt play wow still because here ping was high is there any sort of fix to this?

Perhaps she is using wifi connection which is not stable?