You'll see this warning above any email that looks like a scam, but comes from an address in your Gmail contacts list.
What to do when you see this message
I think the email is a scam
If the email has suspicious links or asks you to do unusual things like send money or personal information, the message may be a scam sent without permission from your contact's email account.
- Don't respond. To be safe, don't reply to the message or click any links.
- Report the message to Google. In the warning message you saw, click Report this suspicious message. The message will be marked as "sent from a compromised account," and that will create a report that's sent to the Gmail team. This helps protect the sender's account from abuse. You'll still get messages from them in the future.
- Let your friend know. If you know the person who sent you the message, let them know about the suspicious message, but not over email. You can suggest that they go through the Gmail Security Tips.
I don't think the message is a scam
If you're confident that the message isn't a scam, click Looks safe or Ignore, I trust this message.