When installing a fresh AR Server on a MSSQL Database with multiple instances present the install log shows:
Make sure the right port number is used for the Database instance or a dynamic port is not set for the instance.
To check the local IP as well as the listening Port number
1- Open SQL Server Management Studio.
2- Connect to the database engine for which you need the port number.
3- Run the following query against the database:
select distinct local_net_address, local_tcp_port from sys.dm_exec_connections where local_net_address is not null;
The above query shows the local IP as well as the listening Port number in this instance it is 1433 default port
To check is a port is Dynamic port:
1- Open SQL Server Configuration Manager.
2- Expand SQL Server Network Configuration.
3- Click on Protocols for <Instance Name>.
4- Right-click on TCP/IP and click on Properties.
5- Click on the IP Addresses tab.
6- Scroll down to IPALL.
7- The port being used will either be listed as TCP Port (which is a static port) or TCP Dynamic Port.