Hello, the avast https scanning causes problems with some https-sites! Those sites (for example the domain-center at 1and1) don’t work and are no displayed. After deactivation of avast https scanning every thing is fine. Please fix this asap, thanks.
There are numerous posts about the https enabled is causing issues.
Some are choosing to disable https scanning for now.
The more information you can give the greater the chance of it being resolved.
e.g. Browser, Operating System and avast version and number.
Part of any problem would be your stating some HTTPS sites and not all HTTPS sites.