Contact form 7 wont upload documents

Hi guys I’ve read all the threads and not yet found an answer!

I created a form on my site that included an “upload file” button that worked for about a year – until a couple of weeks ago.

Now I get “Validation errors occurred. Please confirm the fields and submit it again.”

There is nothing wrong with my form,(no size/format limits etc) and I am not a novice!

Look forward to hearing from someone that’s solved this issue