I'm migrating a few sites to new servers. I created a backup of the database, restored it as a new one on the new database server, set up my site in IIS, deployed the code, and included the new connection string to the new database. When I go to the site, I'm taken to the Umbraco install page. I can't see any of my content, and I can't access the back office either. I'm running Umbraco 7.4.3. I vaguely remember this happening to me a few years ago but I can't for the life of me remember how to resolve it. Please advise!