Friend's invite list empty

I'm working on a unity project that is implementing the invite feature. The first time I tested the invite logic flow it was fine. I saw my coworker's account and sent an invite. The next time I tested it, my coworker's name didn't show up and I couldn't invite them. After having them decline the invite their name showed up and I was able to invite them again. This wouldn't necessarily be a problem except they failed to receive an invite and I can't send them another one and they can't decline/accept it. Now they don't appear on my friends list and I can't test friend invites anymore even when I uninstall and reinstall the build. How can I fix this?