DB2 and PHP not working on Apache2 but on CLI - php

Question

I've installed the IBM DB/2 PHP Extension via PECL. Astonishingly, access to my DB/2 server works flawlessly via PHP CLI by using the following code:
<?php
error_reporting(E_ALL);
ini_set('display_errors', TRUE);
ini_set('display_startup_errors', TRUE);
$connection_string="DATABASE=NAMZPR1;HOSTNAME=172.20.10.162;PORT=50055;PROTOCOL=TCPIP;UID=bouser;PWD=xxx";
$conn = db2_connect($connection_string, "", "");
if ($conn) {
echo "Connection succeeded. \n";
db2_close($conn);
}
else {
echo "Connection failed. " . db2_conn_errormsg() . " \n";
}
?>
when calling the PHP via browser from Apache2 it throws "Connection failed".
I've edited the appropriate PHP.INI file and added the extension as well as added
export LD_LIBRARY_PATH=$HOME/clidriver/odbc_cli/clidriver/lib
to the Apache httpd.conf file.
I am puzzled. It does not work. What part am I missing? Both the PHP CLI and the Apache PHP Module should ouput "Connection succeeded".
The error I get when calling the URL with the PHP is:
Fatal error: Uncaught Error: Call to undefined function db2_connect()
in /var/www/html/db2.php:8 Stack trace: #0 {main} thrown in
/var/www/html/db2.php on line 8
I've managed to load the ibm_db2 module in Apache, here is the output:
ibm_db2 IBM Db2 and compatible databases support enabled Module
release 2.1.7 Binary data mode (ibm_db2.binmode) 1 - DB2_BINARY DB2
instance name (ibm_db2.instance_name) no value Commitment control
(ibm_db2.i5_allow_commit) 0 - DB2_I5_TXN_NO_COMMIT System naming mode
(ibm_db2.i5_sys_naming) 0 - disabled
My message from the Apache Error Log File is
[Thu Feb 09 16:04:33.929426 2023] [php:warn] [pid 629664] [client 172.20.11.18:57220] PHP Warning: db2_connect(): SQLGetDiagRec returned -2 (is the driver working?) in /var/www/html/db2.php on line
8
Edit: I've managed to set the instance name
IBM Db2 and compatible databases support enabled
Module release 2.1.7
Binary data mode (ibm_db2.binmode) 1 - DB2_BINARY
DB2 instance name (ibm_db2.instance_name) db2inst1
Commitment control (ibm_db2.i5_allow_commit) 0 - DB2_I5_TXN_NO_COMMIT
System naming mode (ibm_db2.i5_sys_naming) 0 - disabled
Environment Variables:
export IBM_DB_HOME=/opt/ibm/db2/V11.5
export LD_LIBRARY_PATH=/opt/ibm/db2/V11.5/lib64
export LIBPATH=/home/admini/sqllib/lib
export PATH=/home/admini/sqllib/bin:$PATH
so weired :-(