PHP Startup: Unable to load dynamic library 'php_extension.dll

Symptoms

The following error is logged to a domains PHP error log where 'php_extension.dll' is a PHP extension, and ea-php## is a PHP version:

PHP Startup: Unable to load dynamic library 'php_extension.dll' (tried: /opt/cpanel/ea-php##/root/usr/lib64/php/modules/php_extension.dll

Example for the iconv extension on PHP 7.2:

PHP Startup: Unable to load dynamic library 'php_iconv.dll' (tried: /opt/cpanel/ea-php72/root/usr/lib64/php/modules/php_iconv.dll

Description 

This typically occurs when incorrectly enabling a PHP extension in a php.ini or .user.ini file.

Example:

root@server [~] # cat /home/exampleuser/public_html/php.ini

extension=php_iconv.dll
extension=php_mbstring.dll

Workaround

Remove the lines that are enabling the PHP extension in a php.ini or .user.ini file.

When installing a PHP extension for a PHP version via WHM >> EasyApache 4 or command-line, the extension is automatically enabled via additional .ini files in /opt/cpanel/ea-php##/root/etc/php.d/ where ea-php## is a version of PHP.

Example for the iconv extension on PHP 7.2:

root@server [~] # cat /opt/cpanel/ea-php72/root/etc/php.d/20-iconv.ini
; Enable iconv extension module
extension=iconv.so