When the forum is not accessible at all it's often the fault of the nameserver. You can check this by accessing http://exetools.com. It that page works, but http://forum.exetools.com not, you can edit your hosts file with the correct IP for the forum. Just add the below line in your hosts file and remove the comment when the nameserver doesn't respond.
Code:
# 222.92.105.26 forum.exetools.com
The forum is usually really fast when the nameserver is down, since there won't be 50 search engine bots online downloading the whole forum.