One @gmail.com account shows no email received from 2:17pm ET Dec 15 to 6:05am ET Dec 16. I normally receive ~4 emails per hour, throughout the day and night. After I realized there might be a fault, I sent myself test messages around 6pm ET on Dec 15 and Gmail bounced them with the error:
> 550-5.1.1 The email account that you tried to reach does not exist. Please try double-checking the recipient's email address for typos or unnecessary spaces. Learn more at https://support.google.com/mail/?p=NoSuchUser x62si100799otb.139 - gsmtp
> 550-5.1.1 The email account that you tried to reach does not exist. Please try double-checking the recipient's email address for typos or unnecessary spaces. Learn more at https://support.google.com/mail/?p=NoSuchUser x62si100799otb.139 - gsmtp