Chrome can't load certain sites but Safari can - how can I diagnose the problem?
You did eventing right except for one step.

Making new account.

Quit Google Chrome completely.

Go to the Go menu > Go to Folder.

Enter the following directories in the text field, then press Go.
    ~/Library/Application Support/Google/Chrome/

Locate the folder called "Default" in the directory window that opens and rename it as "Backup default."

Try opening Google Chrome again. A new "Default" folder is automatically created as you start using the browser.

Alternatively you can "teach" your browser.

That is done by adding the :80 to the web address.

Example www.myseite.com:80

Also run the netstat -a -p tcp  to see if https (443) are open)

Last not least, turn off the experimental "Built-in Asynchronous DNS" is Disabled in chrome://flags/