accounts.google.com sets an X-Frame-Options header of SAMEORIGIN which is preventing Google Auth logins from working (accounts.google.com is not the same origin as your www site), and could potentially break other forms on the page, even if the user is not trying to use Google Auth. This seems to be a common issue with Google embeds; try adding &output=embed to the Google auth URL. Alternatively, you can try not loading the Google auth into an iframe, but into the main HTML directly. You will know the issue is resolved when you stop receiving X-Frame-Options errors in the browser console. If all else fails, try disabling Google integration on your site.
I also notice that you may be using the non-www subdomain like a CDN. Make sure you set Access-Control-Allow-Origin headers at that subdomain to allow your www subdomain access to it, or some resources might be blocked.
Neither issue is caused by a flaw in VaultWiki code.