I've met this problem for the first time and a little frustrated.
I'm working on a small contract and send builds from time to time.
My client wasn't able to download attachment for some reasons, so I've uploaded latest build to Dropbox and shared a link with him.
And today he contacts me and tells that he doesn't see the link
I've checked and I see this message - "Upwork has detected a potential risk with the content of this message." When I click on it I see - Verified by Upwork to contain spam, phishing, or inappropriate content)
This is NOT an inappropriate content. This is the result of my work, and my client cannot receive it for 2 days already.
I`m sorry about the inconvenience this had caused you.
Could you please send me a PM with your client name so that I can locate the message and have our team investigate it further? Thank you.