[SOLVED] mod_fcgid: stderr: PHP Fatal error: Class 'mysqli' not found

Hi,

I found this error in earlier posts but didn't find a solution yet.

ISPConfig site throws HTTP ERROR 500 after Installing / Removing PHP 7.
The Debug script only shows PHP Warning: Module 'mysqli' already loaded in Unknown on line 0

Code:

[Sat Sep 23 14:12:39.909950 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP Fatal error:  Class 'mysqli' not found in /usr/local/ispconfig/interface/lib/classes/db_mysql.inc.php on line 31
[Sat Sep 23 14:12:39.909974 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP Stack trace:
[Sat Sep 23 14:12:39.909981 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP   1. {main}() /usr/local/ispconfig/interface/web/index.php:0
[Sat Sep 23 14:12:39.909986 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP   2. require_once() /usr/local/ispconfig/interface/web/index.php:32
[Sat Sep 23 14:12:39.909991 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP   3. app->__construct() /usr/local/ispconfig/interface/lib/app.inc.php:340
[Sat Sep 23 14:12:39.909995 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP   4. app->load() /usr/local/ispconfig/interface/lib/app.inc.php:64
[Sat Sep 23 14:12:39.909998 2017] [fcgid:warn] [pid 13918] [client 91.65.93.101:65127] mod_fcgid: stderr: PHP   5. include_once() /usr/local/ispconfig/interface/lib/app.inc.php:158

Code:

[02:33 ] root@srv1 [/var/log/apache2] $  php --version
PHP Warning:  Module 'mysqli' already loaded in Unknown on line 0
PHP 5.6.30-0+deb8u1 (cli) (built: Feb  8 2017 08:50:21)
Copyright (c) 1997-2016 The PHP Group
Zend Engine v2.6.0, Copyright (c) 1998-2016 Zend Technologies
    with Zend OPcache v7.0.6-dev, Copyright (c) 1999-2016, by Zend Technologies

[02:34 ] root@srv1 [/var/log/apache2] $  which php
/usr/bin/php

... the 'PHP Warning: Module 'mysqli' already loaded in Unknown on line 0' is a result of me putting 'extension=mysqli.so in one or two php.inis...

The binary gives this strange link chain:

Code:

/usr/bin/php -> /etc/alternatives/php -> /usr/bin/php5

Currently I have no idea where to look further...

 

Never mind, purged php completely, deleted all folders from previous/different versions and reinstalled php5. ISPconfig site is back.