Is Avast blocking websites?

About 3.5 hours ago, as I was working in QuickBooks Online, I appeared to have connectivity issues and the site wouldn’t reload. I cleared cache. I rebooted my computer. I rebooted my modem. In short, I did everything I could think of to figure out what was going on. I was intermittently able to access the site, and then got the same error message: Your connection was interrupted. A network change was detected.

I am getting this error message on most websites, including Avast. Sometimes, reloading means the site will load after a couple of tries, including this forum site.

I searched for this error message & QuickBooks Online, and found that the culprit was generally anti-virus software. I turned off all of the core shields and am still having errors.

ETA: I uninstalled Avast and reinstalled from the link in the pinned topic. So far, problems seem to be solved. Leaving this here to help anyone else with this issue so they don’t waste the time that I did this evening in trying to fix it.

I am on Mac OS Big Sur ver 11.4 and on Avast Premium and using Chrome