I am also getting this problem, no web access whatsoever ( Firefox and Chrome )and also blocking email ( Pegasus Mail )
This started a few hours ago so I have removed and re-installed Avast 2015 by restarting the computer in safe mode, running AvastClear.exe, and re-installing the Avast direct from the avast server. the problem persists.
I am also running Win XP sp2 , as are the two other machines on my network, and have no problem with those as I hav'nt updated avast on those and don't intend to until this problem is resolved.
Fault description:
Webaccess blocked because certificate is invalid , the names are mostlyavast
preceeded with a *
example error reports...
"Avast Web Shield has blocked access to this page because the following certificate is invalid *.google.com " when accessing Google UK
"Avast Web Shield has blocked access to this page because the following certificate is invalid *.mathtag.com " when accessing Ebay.co.uk
"Avast Web Shield has blocked access to this page because the following certificate is invalid
www.avast.com " when accessing
https://www.avast.com"Mail shield security exclusion " when trying to use Pegasus Mail to access one.com pop3 server the certificate information says
"issued to *.one.com"
"Issued by COMODO RSA Organisation Validation Secure Server CA"
"Valid From 09/04/2014 to 09/04/2017"
If I disable Avast for 10 mins everything functions as it should.
as noted above, this only started after updating the Avast 2015 program.
any help appreciated.