Upload error: File could not be uploaded for some reason

Hello.
I'm having problems with my form when I want to upload a document.
I received the same message each time, but I don't know how can I solve the issue.
Thanks for your reply.

Can you please answer the following so we can run some tests?

1. How many concurrent files are you trying to upload when you see that error?

2. What's the file sizes of the files you're uploading?

3. What file types are you uploading?

Your answers to these questions will help us because when I did a test submission to your form 72656485717873 (please ignore it), it worked as expected.