I can't fufill your request

Hello everyone, lately ChatGPT has been telling me that “it can’t fulfil my request” even though I’ve asked it to do so several times. I also feel that it’s slowed down a lot and that it’s “learnt” a lot since last Friday. Can you help me?

I would suggest you to reach out OpenAI support https://help.openai.com/en/ or maybe their community forum as there were recent changes added from their end.
Also, I would like to inform you that their Usage Policies have been updated just a month ago.
See also: Usage policies
OpenAI support would be in a better position to explain more about this.