SQL server connection not working

Trying to connect my CodeIgniter 4.5.1 project to a SQL Server (14.0) database. Running on Windows with XAMPP, PHP version 8.2.

I downloaded the appropriate DLLs from Microsoft, put them in my PHP extensions folder and enabled the extensions

In my .env file I entered the database information:

PHP Code:

database.default.hostname = "MYSERVER\TEST"
database.default.database = 'mydb'
database.default.username = 'myuser'
database.default.password = 'mypassword'
database.default.DBDriver = 'sqlsrv' 


I get the following error:

Code:

Unable to connect to the database.
Main connection [sqlsrv]: [Microsoft][ODBC Driver 17 for SQL Server]TCP Provider: Der Wartevorgang wurde abgebrochen.
SQLSTATE: 08001, code: 258

The server is running and the credentials are correct (I triple-checked).

If I connect to the DB the "hard" way (using the same credentials), it works just fine (just dropped code below into my controller):

PHP Code:

        $serverName = "MYSERVER\TEST"; 
        $uid = "myuser";  
        $pwd = "mypassword";  
        $databaseName = "mydb"; 
        
        $connectionInfo = array( "UID"=>$uid,
                                "PWD"=>$pwd,
                                "Database"=>$databaseName); 
        
        $conn = sqlsrv_connect( $serverName, $connectionInfo);  
        
        $tsql = "SELECT id, name FROM users";

        $stmt = sqlsrv_query( $conn, $tsql);  
        if ( $stmt )  
        {  
            echo "Statement executed.<br>\n";  
        }  
        else  
        {  
            echo "Error in statement execution.\n";  
            die( print_r( sqlsrv_errors(), true));  
        }  
              
        while( $row = sqlsrv_fetch_array( $stmt, SQLSRV_FETCH_NUMERIC))  
        {  
            echo "Col1: ".$row[0]."\n";  
            echo "Col2: ".$row[1]."\n";
            echo "-----------------<br>\n";  
        }  
        
        sqlsrv_free_stmt( $stmt);  
        sqlsrv_close( $conn);  


I am probably just doing something incredibly stupid, but I have been staring at this for hours and I am at my wit's end. Anyone have an idea? Thank you for reading.