I cannot upload pictures here

As the title said I cannot upload any pictures
When I try, It shows

Sorry, the file you are trying to upload is not authorized (authorized extensions: jpg, jpeg, png, gif

I have tried jpg and jpeg files but no one works.

Your file might not be a valid jpg. The format must be valid, not only the name.

What is the output of file?

$ file /path/to/your.jpg

And can you upload it to somewhere else like postimages.org?

@jn64’s advice here is a good first step. Also, are you using a browser extension like Privacy Possum? I have to turn off this extension in order to upload images.