When you complete a form, you will need to upload files.
To upload a file, you must :
Click on the "(+) plus" button
"Select" your file
Let the file "Load" at 100%
Click on "View" to see the file
The loaded file is presented on your screen
Click on "Delete" to delete the file or to replace it with another one.
Do not refresh the page
Do not attempt to recharge the file again
The reason is that :
The format is not the right one: I will get a message telling me that the file is not in the right format (if I try MP4 instead of PDF as the accepted format)
The files are too heavy: I will also get an error message, telling me that the format is too heavy
To overcome these problems, you can :
Use either online converter sites to "Convert" your files
Or sites to "Compress" your documents