I finally tracked down the “Blocked Sign-in Attempt” messages on my Gmail account.  My old ReadyNAS NV+ had alerts setup on it using my Gmail SMTP.  Unfortunately Google has limited access to SMTP unless you allow less secure apps.  I didn’t want to allow this on my main e-mail account so I setup a “relay” account that I could enable the less secure access in.

• Create a new G-mail account <account>.relay@gmail.com
• Click on “My Account”
• Under “Sign-in and Security” click on “Connected Apps and Sites”
• Enable the “Allow Less Secure Apps”

Next in the Ready-NAS NV+ Alerts

• Setup you main Gmail account that you did not enable “Less Secure” apps on as the alert contact
• Set your provider as Gmail
• Use your new account username and password (<account>.relay@gmail.com)
• Under Advanced Options
  • SMTP Server: smtp.gmail.com
  • SMTP Port: 587
  • From: <account>.relay@gmail.com
  • Use TLS should be checked

After this you should be able to press the “Send Test Message” button and receive an e-mail at your original account.  This configuration allows you to keep your main account secure while allowing alerts to be directly sent to it.