For me the technical issues are explained by https://ninite.com/help/errors/revocation.html which while a new to how the web certs person may write it doesn't apply, these firewalls and protection suites tend to break down like that blocking the updates and checks.
So either take it up with Avast or do like I do and forgo Avast's sometimes broken web shield. I use Web Of Trust instead.
Bob

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