Teen Sims stuck standing outside high school

Lately ,every time my teen sim goes to school her and all her peers just stand outside of school.I've tried resetting the sims to no avail the sim still receives reprimanding from the teacher and is required to attend detention but it still makes them all just stand there.The sim can only go home if i go onto another sim and bring the teen sim to their lot,I can't leave school and I can't do anything. Any ideas why or fixes?