OpenAI, the company behind the popular artificial intelligence (AI) chatbot ChatGPT, said it has put new sign-ups on hold for the premium version of the AI tool, ChatGPT Plus, due to a high surge in usage after DevDay.

The company’s CEO, Sam Altman, made the announcement via a post on X (formerly Twitter) on Wednesday, Nov. 15. According to Altman, new sign-ups are paused because the platform has exceeded its capacity, affecting users’ quality of experience. Atman said ChatGPT Plus has seen a surge in usage since OpenAI’s DevDay, where it announced some new application programming interfaces (APIs) roughly a week ago.