Letter of Recommendation From a Teacher Not at my School

Hi!
One of the teachers who has written a letter of recommendation for me no longer works at my school, and my school uses Naviance and she’s not in it anymore. How does she submit her letter if she can’t do it through Naviance? Do I just add her as “Other Recommender” on Common App? If I do that, though, some of the colleges I’m applying to don’t allow me to add other recommenders. This is so stupid and counterintuitive, and I’m getting really frustrated.

My guidance counselor told me to have the teacher send him the rec and there’s a way for him to manually input it into Naviance as a gc, apparently. Hope that helps!

My counselor said that he tried to do that, but he couldn’t for whatever reason D: