Server Error. Upload Directory isn't writable.

I have a form with a file upload option. when trying to attach files it give this error. upload directory isn't writable.

I've republished the form several times, tried removing and adding the form to the website. still error. I even get the error when testing the form in preview on jorform. 

please advise. 

We would like to apologize for any inconvenience. The issue should now be fixed as it has been reported immediately and our developers were able to fix it right away. 

Can you check it again on your end and confirm? If by any chance you encounter any further issues, please do not hesitate to let us know.

Thank you.