Unable to connect to specific sites like Gmail, Facebook YouTube

Hello

I have a Win10 Dell laptop where specific sites like Gmail, YouTube, Facebook have stopped connecting  from last two days. It does not connect in any of the browsers. In IE it  gives an error message 'This site is not secured and clicking 'Details' shows 'Your PC doesn't trust this website's security certificate' Error Code OLG_FLAGS_INVALID_CA. Because this site uses HTTP Strict Transport Security you can't continue in the site at this point. Similarly Firefox also shows 'Your Connection is not Secure' Error Code SEC_ERROR_UNKNOWN_ISSUER.
However when I connect my laptop using phone's internet(personal hotspot) all these sites work normally. Other sites like yahoo or amazon work normally from the laptop.

I've not installed any anti virus yet other than Windows defender. I am kind of stuck at this point. Any help will be appreciated