it show me 'Unable to connect'
Unable to connect
Firefox can't establish a connection to the server at files.avast.com.
The site could be temporarily unavailable or too busy. Try again in a few moments. If you are unable to load any pages, check your computer's network connection. If your computer or network is protected by a firewall or proxy, make sure that Firefox is permitted to access the Web.
Alla svar (1)
If I check the HTTP response headers then I see a few redirects (HTTP/1.1 302 Moved Temporarily)
Location: https://www.avast.com/ Location: https://www.avast.com/redirect/ Location: https://www.avast.com/en-us/index
Clear the Cache and remove the Cookies from websites that cause problems.
"Clear the Cache":
- Firefox/Tools > Options > Advanced > Network > Cached Web Content: "Clear Now"
"Remove the Cookies" from websites that cause problems.
- Firefox/Tools > Options > Privacy > "Use custom settings for history" > Cookies: "Show Cookies"
You can remove all data stored in Firefox from a specific domain via "Forget About This Site" in the right-click context menu of an history entry ("History > Show All History" or "View > Sidebar > History") or via the about:permissions page.
Using "Forget About This Site" will remove all data stored in Firefox from that domain like bookmarks, cookies, passwords, cache, history, and exceptions, so be cautious. If you have a password or other data from that domain that you do not want to lose then make sure to backup this data or make a note.
You can't recover from this 'forget' unless you have a backup of the involved files.
If you revisit a 'forgotten' website then data from that website will be saved once again.