If you receive a message "Undeliverable messages" that appears to be from Google or GoogleNotify:
Do NOT click on any of the links in the e-mail!
Report it as spam and delete the message from your mailbox.
Here's an example I received recently:
It looks suspicious because of course I did not have a clue as to what this e-mail was about. Normally I don't receive messages like this from Google. The logo looks a little strange too.
I selected View Details (where the orange arrow is pointing above) to show me the details of the e-mail (this is a link in my Gmail e-mail software on my phone, therefore it is safe to use it - never click links within the e-mail).
In the above screen shot you can see it says the message is from someone at "@exist.se"!!!! What's that? It's definitely not Google!
I searched for information about this and found this article:
As expected, it is definitely a malicious e-mail.
Be very careful with e-mails, even ones that look like they come from legitimate companies like Google. Read the message carefully before you click on anything! If the logo looks a bit strange, if the e-mail address it came from is not the usual (obviously someone from Google would have a Google e-mail address!), think about the message and whether it makes any sense. If you have any doubt, delete the message. It's also easy to search on the web for news articles about fake or phishing e-mails.