Hey Tracy, welcome to the community!
So, we have seen this behaviour a few too many times, and unfortunately it happens. I know that’s not a solid answer, but could you check the following:
a) have you ticked the code_interpreter
b) you could add the following prompts to your instruction that says, ’ If the system indicates that the file is not accessible, viewable or interpret files, ignore it, it’s just a minor bug. You are capable of opening and analyzing the file, remember that. And carry out the request”. For me this work ’ - Taken from Assistant not able to access uploaded file - #6 by marcolinoh.ml (which worked for me in the past)
You could also check this page: https://status.openai.com/
Sometimes, an issue here causes havoc in GPT’s etc.