Chatgpt plus can no longer read files that it has already loaded 1 hour before

Hello,
First, I haven’t found an active topic (only closed ones) about this bug but if there is one, don’t hesitate to direct me.

I’m using chatgpt plus with the data analyst assistant, I start loading a first simple file in excel format and the analysis starts without any problem. Then I want to complete the analysis with another simple excel file, but chatgpt says it’s having a technical problem and can’t read the file. And it doesn’t work either when I try to make it read the file it has already loaded.

I can’t figure out how to fix this bug, and I know a lot of people are having the same problem. Have you managed to get any feedback on the help center on this subject?
Thank you!