Daughter being excluded

My daughter is 4.5 years old and having issues at school. It seems as though there is one girl in particular who started excluding her, and now the rest of the girls in her class are too. They tell her they don’t want her to play with them and ignore her when she tries to join in their games. I’ve spoken with the teacher and apparently she is very kind and respectful of others in school, and from what I’ve observed she isn’t loud or rude in any way to others and it seems like she is just being excluded for the sake of it. I will add that she is quite shy and introverted as well and extra sensitive to rejection. I’ve told her that there’s nothing we can really do if someone doesn’t want to play with us but that we can try to find other friends and not let it get to us but I think she is having a hard time grasping all of this. My question is, what practical advice/coping skills can I give a four year old who is being excluded and having a hard time making friends at school?