Squid starts blocking websites, even though the blacklist is empty

[merajc]

I have installed Squid through the Package Manager on the following version of pfSense:
2.3-RELEASE (amd64)
built on Mon Apr 11 18:10:34 CDT 2016
FreeBSD 10.3-RELEASE

I haven't installed SquidGuard or anything else, but enabled Squid and ticked the Transparent Proxy checkbox. When I do this, websites such as TakeALot.com and Bacardi.com become blocked (www.takealot.com took too long to respond. ERR_CONNECTION_TIMED_OUT), while Facebook.com and Twitter.com remain accessible.

There is nothing on the blacklist, it's a clean configuration. Why are these websites being blocked?

I tried to add those two blocked ones to the whitelist, but it doesn't make a difference. I also tried to add Facebook.com to the blacklist, but it remains accessible.

Please assist.