It may be that her anger isn't based on something you actually DID but in her mind it is somehow connected to you. If you can't get her to talk about it, so that you have a chance to clear the air, there may be nothing you can do. You can't mend things till you know what's broken. Being a blood relative unfortunately doesn't guarantee that two people will get along, and anger between mother and daughter can be very bitter. Try to get her to talk about it; ask more than once if you have to even if asking makes her angry.