Junior RF Engineer red flags / deal breakers ??

Hello everyone, I hope you are all doing well! I have a question for the senior RF engineers: If you are interviewing a candidate for a junior position, what would be the red flags or the deal breakers that would instantly make you decide to reject their application ? Also, if you have a junior on your team, what would be the minimum expectations you would have for him/her to be successful in their role ? Thank you!