How to connect to SQL server remotely with windows authentication in PHP7?

Solution:

1. You must remove "UID"=>"ramunasc" from $connectionInfo. When you set "UID" connection option and not set "Authentication" connection option, the PHP driver tries to use SQL authentication.
2. It's important to note, that when using windows authentication, the Web server's process identity or thread identity (if the Web server is using impersonation) is used to connect to the server, not an end-user's identity. That's why you can connect to the server with SQL Server Management Studio (authenticated with your windows credentials), but your script fails.

Test environment:

1. SQL Server 2005 Express edition, with mixed authentication mode.
2. Apache 2.4 with PHP 7.1.12 and Microsoft PHP Driver for SQL Server (php_sqlsrv_71_ts_x86.dll, version 4.3).

Connect with windows authentication (working example):

<?php
$server = '127.0.0.1';
$cinfo = array(
    "Database"=>'master'
);

$conn = sqlsrv_connect($server, $cinfo);
if( $conn === false )
{
    echo "Error (sqlsrv_connect): ".print_r(sqlsrv_errors(), true);
    exit;
}

$sql = "SELECT CONVERT(varchar(32), SUSER_SNAME())";
$stmt = sqlsrv_query($conn, $sql);
if( $stmt === false ) {
    echo "Error (sqlsrv_query): ".print_r(sqlsrv_errors(), true);
    exit;
}

$row = sqlsrv_fetch_array($stmt);
echo "Login name: ".$row[0];

sqlsrv_free_stmt($stmt);
sqlsrv_close($conn);
?>

In my case the result is "Login name: NT AUTHORITY\SYSTEM".

Connect with SQL server authentication (working example):

<?php
$server = '127.0.0.1';
$cinfo = array(
    "Database"=>'master',
    "UID"=>'username',
    "PWD"=>'password'
);

$conn = sqlsrv_connect($server, $cinfo);
if( $conn === false )
{
    echo "Error (sqlsrv_connect): ".print_r(sqlsrv_errors(), true);
    exit;
}

$sql = "SELECT CONVERT(varchar(32), SUSER_SNAME())";
$stmt = sqlsrv_query($conn, $sql);
if( $stmt === false ) {
    echo "Error (sqlsrv_query): ".print_r(sqlsrv_errors(), true);
    exit;
}

$row = sqlsrv_fetch_array($stmt);
echo "Login name: ".$row[0];

sqlsrv_free_stmt($stmt);
sqlsrv_close($conn);
?>

The result is "Login name: username"

It's works

$server = "tu_server.com";
$databaseName = "BaseDEV";
$applicationClientID = "DOMAIN\\user";
$applicationClientSecret = 'password';
$connectionInfo = "Database = $databaseName; ColumnEncryption = Enabled; KeyStoreAuthentication = KeyVaultClientSecret; KeyStorePrincipalId = $applicationClientID; KeyStoreSecret = $applicationClientSecret;";
$conn = new PDO("sqlsrv:server = $server; $connectionInfo");