ChatGPT can reach capacity when there’s a heavy load on its servers, caused by many users prompting it at the same time. If you’re getting the “at capacity” message, give ChatGPT a cool-down period by waiting a few minutes before trying again.
Sometimes, you might have to wait a half hour or more. You also have the option to subscribe to ChatGPT Plus if you want your requests to have priority, even during peak times.