I recently restored a backup of an Org_MSCRM database which was then imported as a new organisation in Deployment Manager. After successfully creating the organisation, I then attempted to navigate to the organisation which displayed a “404 Page Not Found” error. What was odd was that I could still load the default organisation for the deployment, but not the organisation I had just imported.
I managed to fix this issue by performing an IISRESET on the CRM server. Check that you can load all organisations after performing this action.