I tried to upload the files to dropbox. However I faced these issues:
1. When I have enabled upload to dropbox the droploader contact form 7 field (the field is mandatory) seems to be null, despite the fact that I have uploaded a file.
2. When I make the droploader field not mandatory and I finally try to submit the from, I take a 500 error as a response.
I tried to reproduce this bug on my site, but no luck. Everything works fine.
So, for now I’m not able to fix this error on your site, because I can’t figure out what same is wrong.
If you want, I can give you refund for this item, but probably I can’t fix this issue.