回答ありがとうございます。
Avast以外は使用しておりません。
案内いただいたDNS設定も試してみたのですがうまくいきませんでした。
最後の方というのがどのあたりまで載せればいいかわからないのですが、
下記の内容でよろしいでしょうか。
[2018-11-18 12:34:02.064] [warning] [servers ] [ 5076:10880] There is no suitable url for 'program' with IPv6 and https
[2018-11-18 12:34:02.134] [info ] [usnca ] [ 5076:10880] USN cache successfully saved to the disk.
[2018-11-18 12:34:02.134] [info ] [instup ] [ 5076:10880] Saving product state.
[2018-11-18 12:34:02.135] [info ] [instup ] [ 5076:10880] Persistent Guid = 4ad6099e-5f08-4ad1-91ef-9f0cc572c8e2, Created = 00:58:57 12.09.2018
[2018-11-18 12:34:02.135] [info ] [mutex ] [ 5076:10880] The ownership of the global synchronization mutex has been released.
[2018-11-18 12:34:02.135] [info ] [event_rout ] [ 5076:13280] Handler unregistered: system.network.connectivity_changed, Module: C:\Program Files\AVAST Software\Avast\setup\Instup.dll
[2018-11-18 12:34:02.137] [info ] [event_rout ] [ 5076:10880] Handler unregistered: burger_client.send_event.7, Module: C:\Program Files\AVAST Software\Avast\setup\Instup.dll
[2018-11-18 12:34:02.137] [info ] [event_rout ] [ 5076:10880] Handler unregistered: burger_client.flush, Module: C:\Program Files\AVAST Software\Avast\setup\Instup.dll
[2018-11-18 12:34:02.150] [info ] [mutex ] [ 5076:10880] The ownership of the global synchronization mutex has been released.
[2018-11-18 12:34:02.150] [error ] [instcont ] [ 5076:10880] Error returned by Instup, return code 41223 (0x0000A107) [Server is down]
[2018-11-18 12:34:02.173] [info ] [instcont ] [ 5076:10880] 2018/11/18 12:34:02 END: Avast installer/updater, return code 41223 (0x0000A107) [Server is down]