Avast Virus Signature Update

[TToD 1]

I don't think this is a blocked site issue as I can access the various Avast sites in my browser.
But when trying to update the virus signatures the Avast client does not seem to communicate with the Avast server.

In the update section there is a check box for streaming the update - the issue occurs whether this is checked or not.
It has been happening on different versions of the avast client since about the beginning of this year.
I'm using the Free version of Avast.
It happens on different AirVPN servers in different countries (US, Canada, UK).

The only way I've been able to update the signatures is to disconnect from AirVPN to do the update.