Odd emails

For several years I have used Norton 360, for Windows and Android, for a total of 5 devices, which include two mobile phones. From time to time I receive emails from norton@secure.norton.com , informing me that I am not using all the options of the product.

This morning I received and email on my phone from the above email address with the subject line Reminder: You're not using all your security features. It goes on to say that 'you can protect up to 5 devices, but your protecting 5. Mobile devices need security, too Protect them with the same subscription you use on your PC. There is then a link 'Install on another device'  [Obviously I have not followed the link] Also on the PC when I open  the screen below I see a similar 'offer'

  This link on the above is 'live' Clearly this makes no sense, can someone throw any light on this.

Edit: it's the first time I have tried to insert a screen shot, and I seem to have failed. The screen below refers to the main classic page when you open Norton 360.