Daughters not talking to each other

My daughters don’t talk to each other. At all. They were close when they were little, then as they grew, they started to fight more, then my older daughter withdrew which caused a lot of sadness for my younger daughter. They had some communication and would occasionally joke around or get together for something but it was few and far between. Mostly it is just silence with word bombs thrown at each other periodically.

Over the summer my older daughter made an enormous effort to talk with my younger daughter and they spent a lot of time together. They played video games together and went on walks. It was unbelievable and I was so relieved and happy about this. Then we went on a family trip and while in the car, my younger daughter fell asleep. When we stopped at a rest area, I had to wake her up and she was kind of out of it. My older daughter said something to her that wasn’t mean in any way, but my younger daughter took it to be mean and completely lashed out at my older daughter. Ever since that day, they have completely stopped talking to each other. I over heard my older daughter say that her sister doesn’t like her and she has no idea why. But instead of trying to talk it out or deal with it in any way, she has completely shut down, put up the wall of anger, and stopped talking to my younger daughter.

I don’t know if they will bounce back from this one. I am struggling with whether or not I should intervene. Not to tell them to get along, but just talking about how it’s better to keep communication open and unresolved feelings have a way of re-surfacing in other ways. But both of them are so embedded in their story that the other one is wrong and mean, etc. that they won’t even entertain the thought that they could be friends. They won’t even stay in the same room as the other one.

It feels so terrible as their mom to be in the middle of this. My instinct is to fix it, but I can’t. So I feel helpless and like a complete failure because I obviously didn’t teach them enough about emotions and how to be in a relationship. My sister and I never had a good relationship and I didn’t want that for my girls. I really wanted them to be close and be friends. I thought we were on the right track with that and then it got completely derailed and I never figured out how to get back on track.

I really do feel like a failure every day because of this. I don’t know how to untangle my emotions from their thoughts, actions, and results.