First of all find out the reason of hatred. If he/she has a genuine reason of hating you now you know. If it’s your fault talk to him/her and try to make things right.
If it’s not don’t stop talking. Never let your ego burn the friendship. Talk to him/her. Try to understand his/her point .If you feel there is a difference in perspective talk about it.
One thing that can save friendship is just don’t stop talking.
If he/she still hates you even after all the efforts let him/her and move on. Make new friends. :)
