Hi I have migrated our forums from phpbb2 to 3 (the latest version) and in our Google webmaster tools we now have 229,981 not followed errors and climbing every day. The error i get is a 301 There was a problem with active content or redirects. However when pressing the link or typing it in the browser you can find it and even if you press fetch and googlebot you get a success but then inside the message in webmaster tools you get HTTP/1.1 301 Moved Permanently.
So i went into the ACP and checked the googlebots permissions and have BOT ACCESS in all parts of my forum but the error still occurs.
If you put the link into your browser it works which is strange so i think it’s down to some sort of permissions or a redirect but everything seems to be set up right.
Try downloading a User Agent changer for your browser and browse your site. Use the user agent 'Googlebot' without the quotes and see if you redirects.
Typically 301 redirects will redirect your browser so quick that you won't notice it. You'll have to try and notice the quick changes in your URL bar while accessing the URLs listed on Google.