Google Chrome "Privacy Error" on everything, after internet re-connection

So a tree fell in my yard and knocked down the cable that supplies internet service to my house. AT&T, which is my service provider, came over and re-connected the cable. The internet works normally now, except for one very frustrating thing that I just noticed. Google Chrome now throws me a “privacy error” on all sorts of sites, even Wikipedia, and I have to click through the “advanced” tab and click “proceed to wikipedia.com anyway” just to access it. The images on Wikipedia likewise come up as non-loaded images with the little “broken image” icon. If I right-click them and choose “open in new tab”, I get another privacy error. Then if I choose to proceed to the image anyway, it opens and then suddenly all the images on Wikipedia are viewable. But it’s reset after each browsing session and I have to do it over again. Quora is also similarly affected, plus a variety of other sites. I feel like maybe 25% of all websites give me this “privacy error”. Also, the SDMB website is inaccessible in Google Chrome.

Firefox doesn’t have this issue, only Chrome.

The odd thing is, it only happens on my laptop, a Macbook Air, and NOT my desktop, an iMac Pro. (This led me to wonder if maybe it was a sheer coincidence about the cable being disconnected - but I hasten to add that this ONLY started happening after the reconnection of the internet service. It would be a hell of a coincidence, right?)

I know there are more specialized forums where I could ask about troubleshooting this, but I figured someone here might well know the answer. Does anyone?