Executing stored procedure in Microsoft SQL through PHP

Question

I'm trying to execute a stored procedure in a Microsoft SQL database through PHP 7.4, including the passing of variables. I'm able to successfully execute it through SSMS with the following command.

GO

DECLARE @return_value int

EXEC    @return_value = [dbo].[UDX_Page]
        @message1 = N'GROUP,user,.Notification Group,Is this thing on?  [WebMSG]',
        @message2 = NULL

SELECT  'Return Value' = @return_value

GO

It seems that it is expecting message1 as a varchar(200) and message2 as text, though the latter can be NULL. I've tried to call it through a couple different iterations of the following PHP code. I get no errors, but it doesn't seem to execute, so I must be doing something wrong.

<?php

    $conn = sqlsrv_connect( $serverName, $connectionInfo); //connection info redacted
    echo "<b>DATABASE: </b>";
    if( $conn ) {
         echo "Connection established. (" . $serverName . ")<br />";
    }else{
         echo "Connection could not be established.<br />";
         die( print_r( sqlsrv_errors(), true));
    }
    $message1 = 'GROUP,user,.Notification Group,Testing -DW [WebMSG]';
    $message2 = NULL;
    $sql = "EXEC [dbo].[UDX_Page] @message1 = N'" . $message1 . "', @message2 = NULL";
    $stmt = sqlsrv_query($conn, $sql);
    if( !$stmt ) {
        die( print_r( sqlsrv_errors(), true));
    }
?>

And also with the following:

<?php
    $conn = sqlsrv_connect( $serverName, $connectionInfo); //connection info redacted
    echo "<b>DATABASE: </b>";
    if( $conn ) {
         echo "Connection established. (" . $serverName . ")<br />";
    }else{
         echo "Connection could not be established.<br />";
         die( print_r( sqlsrv_errors(), true));
    }
    $message1 = 'GROUP,user,.Notification Group,Testing -DW [WebMSG]';
    $message2 = NULL;
    $sql = "{CALL [dbo].[UDX_Page] (?,?)}";
    $stmt = sqlsrv_query($conn, $sql, array(&$message1, &$message2));
    if( !$stmt ) {
        die( print_r( sqlsrv_errors(), true));
    }
?>

Similarly, when I try it in Python, I'm having similar issues where nothing seems to happen. It recognizes that I need two variables to be passed and complaints if I don't (even if one is None). But it doesn't seem to actually do anything. Any I missing some final execution command?

#/bin/python3
import pyodbc

cursor = cnxn.cursor() #Connection info redacted

SQL_STATEMENT = '{call UDX_Page(?,?)}'
message1 = 'GROUP,user,.Notification Group,Test #7 -DW [WebMSG]'
message2 = None
values = (message1, message2)
cursor.execute(SQL_STATEMENT, (values))

Any ideas?