I have a premium account - all of a sudden I'm limited to 40 minutes

Hi. I've been using a premium account for the last 3 years. All of a sudden, in the past 2 weeks, when I try to schedule a meeting that lasts for 1 hour, I receive a notification that I'm limited to 40 minutes because I have a basic account. But I've been using this same premium account for literally 3 years. What's going on and how can I fix this?

Thanks.