Php_openssl.dll not found

Nextcloud version (eg, 12.0.2): 18.0.3.0
Operating system and version (eg, Ubuntu 17.04): Debian 10
Apache or nginx version (eg, Apache 2.4.25): Apache 2.4.38
PHP version (eg, 7.1): 7.3.14

The issue you are facing:
Many erros about missing php_openssl.dll.

Is this the first time you’ve seen this error? (Y/N): Y

Steps to replicate it:
actually I dont know how it happend.

The output of your Nextcloud log in Admin > Logging:

[PHP] Error: PHP Startup: Unable to load dynamic library 'php_openssl.dll' (tried: /usr/lib/php/20180731/php_openssl.dll (/usr/lib/php/20180731/php_openssl.dll: cannot open shared object file: No such file or directory), /usr/lib/php/20180731/php_openssl.dll.so (/usr/lib/php/20180731/php_openssl.dll.so: cannot open shared object file: No such file or directory)) at Unknown#0

GET /ocs/v2.php/apps/serverinfo/api/v1//basicdata?format=json
from ***.***.***.*** by ******* at 2020-04-04T19:28:32+00:00

The output of your config.php file in /path/to/nextcloud:

<?php
$CONFIG = array (
  'instanceid' => '********',
  'passwordsalt' => '**********',
  'secret' => '********',
  'trusted_domains' => 
  array (
    0 => 'cloud.barner.online',
  ),
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'datadirectory' => '/mnt/data/nextcloud/',
  'dbtype' => 'mysql',
  'version' => '18.0.3.0',
  'filelocking.enabled' => false,
  'overwrite.cli.url' => 'http://cloud.barner.online',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'nextcloud',
  'dbpassword' => '********',
  'installed' => true,
  'maintenance' => false,
  'mail_smtpmode' => 'smtp',
  'mail_sendmailmode' => 'smtp',
  'mail_from_address' => 'noreply',
  'mail_domain' => 'barner.online',
  'mail_smtphost' => 'mail.barner.online',
  'mail_smtpport' => '465',
  'skeletondirectory' => '',
  'force_language' => 'de',
  'knowledgebaseenabled' => false,
  'theme' => '',
  'loglevel' => 2,
  'updater.release.channel' => 'stable',
  'app_install_overwrite' => 
  array (
    0 => 'rainloop',
    1 => 'loginviapost',
  ),
  'mail_smtpauth' => 1,
  'mail_smtpname' => 'noreply@barner.online',
  'mail_smtppassword' => '********',
  'mail_smtpsecure' => 'ssl',
);

The output of your Apache/nginx/system log in /var/log/apache2/error.log:

PHP Warning:  PHP Startup: Unable to load dynamic library 'php_openssl.dll' (tried: /usr/lib/php/20180731/php_openssl.dll (/usr/lib/php/20180731/php_openssl.dll: cannot open shared object file: No such file or directory), /usr/lib/php/20180731/php_openssl.dll.so (/usr/lib/php/20180731/php_openssl.dll.so: cannot open shared object file: No such file or directory)) in Unknown on line 0
[Sat Apr 04 21:21:50.259896 2020] [mpm_prefork:notice] [pid 32427] AH00163: Apache/2.4.38 (Debian) OpenSSL/1.1.1d configured -- resuming normal operations