why gmail accnt can't syn in google chrome.

[marksantos]

Hello everyone, i have a question for content filtering or site blocking. what is the best way on how to block all website then allow whitelist website sample ("gmail, yahoo, globe.shop.com.ph")

ill tried config
using squid proxy

Install Squid & configure
Install Squidguard & configure
Configure WPAD
Force users to use proxy by blocking tcp80,443
in squidguard, common acl , searchengine to whitelist
in squidguard, common acl , webmail to whitelist
In Squidguard, target categories, ill add manual domain of gmail.
In Squidguard, set default ACL to Deny

but my problem is why gmail account cant sync. if i try logging in my account, it will log out immediately