sqlsrv_query isn't working as expected

Question

I'm in a vocational training right now and my task is to create a web-formula for accounting stuff. The server is running IIS 6.2 on Windows Server 2012 R2, PHP 7.2.1 and I finally got the MS PHP SQL Extension running.

Besides my code being a stackowerflow patchwork, it kinda works, only that I cant figure what I did wrong with the query. On submitting the formula it says Transaction rolled back, and I really don't know why. The query is, when pasted into MS SQL Server Management Studio, successfully executed, but not in the form.

$serverName = "server\sqlexpress";
$connOptions = array( "Database"=>"123", "UID"=>"456", "PWD"=>"xxx");
$conn = sqlsrv_connect( $serverName, $connOptions );

if( $conn === false ) {
    die( print_r( sqlsrv_errors(), true ));
}
if ( sqlsrv_begin_transaction( $conn ) === false ) {
     die( print_r( sqlsrv_errors(), true ));
}

/* This is the query */
$sql1 = "INSERT INTO Person (Kundennummer, Vorname, Nachname, Strasse, Hausnummer, Etage, Email) VALUES (?, ?, ?, ?, ?, ?, ?)";
$params1 = array($kundennummer, $vorname, $nachname ,$strasse, $hausnummer, $etage, $email);
$query1 = sqlsrv_query( $conn, $sql1, $params1 );

/* This is where it rolls back the transaction */
if($query1) {
    sqlsrv_commit( $conn );
    echo "Transaction committed.<br />";
} 
else {
    sqlsrv_rollback( $conn );
    echo "Transaction rolled back.<br />";
}
sqlsrv_close($conn);

The Connection is working, because if i replace $sql1 with

$sql1 = "SELECT 'Hello world'";

it says commited. Any guesses? Thanks alot, and, in case you seeing some more bad stuff happening in my code, feel free to correct me.

Answer 1

And suddenly i've got the answer. When I added echo(print_r(sqlsrv_errors(), true)); to the code, it says "INSERT permission was denied on the object [...]", so I added permission to the user. Problem solved, thanks to this answer