I received the DropBox email below from no-reply@em-s.dropbox.com claiming my files are about to stop syncing. Although the email "From" address is legitimate(coming from dropbox.com), I know I can never trust it because email addresses can be easily spoofed. Spoofing means sending an email address from one email account and changing the "From" address to make it appear as if it came from another email account.
The no-reply@em-s.dropbox.com DropBox Scam Email

So, instead of clicking the "View your account" link in the email, I hover my computer mouse over it to see where it goes. Not surprised, the link does not go to dropbox.com, instead, goes to a phishing website that asks visitors to sign in.
The aim of the scam is to trick potential victims into signing into the phishing website. If this is done, their Dropbox account credentials will be sent to the scammers behind the email scam. Therefore, if you clicked the link in the email scam and attempted to sign in, please change your password.
For Dropbox users with 2-Step Verification or Two-factor authentication, the scammers will not be able to sign into their account with their passwords, but we recommend changing their passwords anyway.
Remember, always go directly www.dropbox.com to sign into your account, instead of clicking on a link.