Help to fix my son laptop

Hi to all computer expert

I recently add a Chrome extension called BlockSite to my son's Windows 10 laptop. I deliberately add facebook.com and roblox.com to be restricted web site. I changed my mind tonight and try to let my son go to 2 banned web sites. I simply remove two urls from the restricted web site list, he still cannot access the site. I even remove BlockSite extension from his Chrome browser but it does not help. I reboot his laptop many times, no luck so far.

May I know how to fix this problem for my son ?

Please kindly shed me some light.

Thank you for your help in advance.