I am unable to download either offline installer; I can download both online installers
Why ?
What errors are you getting ?
No problem here, just downloaded the avast free off-line installer.
See attached images, I changed the file name to avast_free_antivirus_setup_offline-20-9.exe for clarity.
When I click on either online installers, a new tab in Chrome opens and a dialog appears asking where to save and allows me to change file name.
When I click on either offline installers, a new tab opens for a second then closes itself with no dialog appearing.
I have successfully been downloading offline installer for years just not working today.
Update: if I copy the offline installer address, then paste in address bar for new tab in Chrome then it downloads, so only problem is clicking on original link doesn't work
What if you try right clicking on the offline installer you want and select Save As ?
That's the way I normally do it, using firefox (my default browser), I don't use Chrome, so I don't know if it has that option (I would be surprised if it didn't, its fairly common).