I currently migrated my old ePO server from 5.3 to 5.9 and performed a disaster recovery snapshot which I then backed up the database to restore onto the new server. I have installed SQL server 2016 and successfully restored from backup of the ePO database. When attempting to install 5.9 and restore from snapshot, I am unable to establish a database connection. I've ensured that the Browser and SQLServer services are running and made sure TCP/IP is enabled as well as the IP configuration is active/enabled. When entering the "Database server", I am entering the computer name of the new server which SQL is installed on and using the default named instance "MSSQLSERVER". Not sure what I am missing here? The Old Server was running Server 2012 R2 and SQL Server 2012. New Server is on Windows 2016 and SQL Server 2016 and reusing the same name as the old one. I have successfully performed the same procedures previously and did not have any issues.
Updated SQL Server 2016 and rebooted. Issue is resolved and connected to database to perform installation from snapshot.