How to deal with ChatGPT's "Refusal"?

Has anyone else met a problem like this?


I have uploaded a pdf file to let GPT-4o analyse it. However, ChatGPT always says “I can’t” such as “I can’t acess the file”, “I can’t understand what you means”. It is very strange, I am sure a few days ago when I upload the same file it can indeed access and analyse it. In addition, when I tell GPT-4o use canvas to write code, it also gave me a “refuse” to do so and answer me like it doesn’t know what canvas is. This is what I met in recent days, and it makes me can’t use ChatGPT to do anything. I look forwards to a solution in this situation. Thanks!