In our real life, surely, there are certain reasons, at least for him/her!

You could try and talk with your friend as open communication is always a good idea. If you find out that you have done something to offend them, then this gives you the opportunity to explain the situation, apologise and try to rectify it if you think that is reasonable. If they refuse to talk to you, then you should accept that this is maybe not your problem, accept that you are powerless to do anything about it, and move on. This is easier said than done of course.

You should forget him/her and search for a serious partner. This issue happens many times, you can say it is common on italki .

Talk to hom, maybe he has an explanation

No masy not in italki I meant in our real life