Just wanted to clarify one thing, we never lost access to the forum software or the content of the forum. That is all hosted on our server, so we have full access to it. And the data is also continuously backed up, so in the event of a server failure the forum will be restored to the point it was when the server failed.
The issue we faced was related to the old domain name itself, since we have no control over it (don't own it, or have access to the domain account it is tied to). So when it changed the dns servers from ours to a different one, the forum went down.
With the current domain, this will not be a problem as we do own it. It will just take some time now to get people used to coming to this domain instead of the old one.