What is this alert about: Fitbit may not have a valid digital signature?

The Fitbit app was installed on my computer  August 2016. Since last week I have been receiving this

 Firewall Alert:  Fitbit does not have a valid Digital Signature

 Once I get this alert and click okay it takes some time to login to the app.

But my question what is the significance of this alert? 

Fitbit tech has never notice this before and suggested I make inquiries with Norton. There has been some trouble with there firmware updates. I have not received it as yet to install. 

Will this alert affect any firmware updates submitted by Fitbit?