Hi!
I'm getting this error when I try to upload a PDF file with a UTF-8 file name (ex: Aceptaci贸n.pdf)
I'm using the 'Content-Type': 'application/json;charset=UTF-8' header in a axios POST, but is not working...
Any ideas?
I need to be able to upload PDF files with UTF-8 names because my users speak spanish.
Thanks!

This is not an issue with the picker. It's difficult to recommend what to do. You could try url encoding the filename and see if your server supports that. Though that's probably non-standard behaviour.
I see conflicting information on how to handle non-ascii filenames. There is a header extension that allows for providing an encoded version of headers. However I see other notes that this should not be used for filename. But React Native is the one erroring when you use a non-ascii character in the http header. You should report this in react-native and see what the proper way to post something with a non-ascii filename in RN is.
In case someone gets stuck on this one like me. Here is a possible workaround (as okhttp is still broken - this works if you dont absolutly need to keep the filename intact for uploading for instance, which is rarely the case.) :
const fileName = (file.fileName || "document.pdf").replace(/[^\x00-\x7F]/g, "");
const pdf = { uri: file.uri, type: file.type || "application/pdf", name: fileName };
I have found work around for this see my answer on
Stackoverflow
Most helpful comment
In case someone gets stuck on this one like me. Here is a possible workaround (as okhttp is still broken - this works if you dont absolutly need to keep the filename intact for uploading for instance, which is rarely the case.) :