AVG Free Mac blocks certain web sites

AVG Protection
6

Hi David,

We will check this for you.
Can you tell the version of your Mac OS?

4

Hi David,

We will check this for you.
Can you tell the version of your Mac OS?

2

It is El Capitan 10.11.6

3

Thank you for clarifying, David. 
To identify the component that causes the issue, we'd suggest you to disable each component individually & check the issue. (Start with disabling file shield - Check the issue - If issue persists, re-enable file shield & proceed with other components till you identify).

5

The component that blocks the web sites is Web Shield. When I disable it I can access any web site.

1

Appreciate your efforts in working towards fixing the issue, David.
From your description, it seems that the mentioned 3 sites are legitimate.
In this regard, you can exclude those sites from Web Shield by following the steps mentioned below 'Set exceptions' in this article. 
Please try the above step & let us know if it helps.