direct selection handles not working properly

HELP! I have not used Illustrator 2021 for awhile and am trying to edit shapes by selecting handles with the direct selction tool. Sometimes the handles work, in a very jerky manner, and sometimes they won't move at all! I'm so used to working with these handles easily. I'm so upset. Am I doing something wrong? I've been using Illustrator for years so this is weird. I even viewed the beginners tutorial on it to make sure it hasn't changed. Maybe it's corrupt? THANK YOU!!!!!