"the add-on could not be downloaded because of a connection failure"

Avast Free Antivirus / Premium Security
1

Hi, when trying to download HTTPS Everywhere, any stable version (all I tested it on), I received the following notification from my Firefox Browser:
“the add-on could not be downloaded because of a connection failure”

I disabled all Avast shields for 10 minutes, and then the download worked.

What is the cause of this problem, and what is the solution, besides disabling shields temporarily?

Thanks.

Edit: I have Windows Firewall, running Windows 7, in case that is of importance in regards to this question.

2
  • Which Avast…? (Free/Pro/IS/Premier)
  • Which version…?
  • OS…? (32/64 Bit…? - which SP…?)
  • Other security related software installed…?
  • Which AV(s) did you use before Avast…?
3

  1. Which Avast…? (Free/Pro/IS/Premier)

  2. Which version…?

  3. OS…? (32/64 Bit…? - which SP…?)

  4. Other security related software installed…?

  5. Which AV(s) did you use before Avast…?

  6. Free

  7. 2015.10.2.2214

  8. Windows 7; 64 bit; SP1

  9. Windows Firewall

  10. None

4

Perform a clean installation of the latest avast version and see if the problem still is there:
https://forum.avast.com/index.php?topic=168680.msg1199245#msg1199245

5

I did the reinstall and the problem is still there.

6

Disable HTTPS-scanning in the web shield. Does it work now…?

7

Yes, disabling HTTPS scanning in, ‘settings → active protection → web-shield → customisation’, fixed the problem, thank you Asyn.

8

You’re welcome.

9

In my eyes, this isn’t a fix but a bypass. I’ve reported this to the Moderates and hope we’ll get an answer as to when the problem will be fixed.

10

Yes, it’s a workaround.