Credits exhausted

When I joined Discord some time ago, I generated images and never encountered the following message. When did things change? In the past I had generated more images within a month's time than I have this month. I am on a paid server and have been since joining Discord. Also, The “fast” generations haven't been as fast as the regular ones. Not sure why and not sure if that has affected my account.

Credits exhausted

You've run out of hours on your plan for this month. You can either:

• Purchase more fast hours with a button below, or
• Use /subscribe to upgrade to the standard plan, for more fast hours and unlimited relax usage.