E_ERROR

When seeking help with this issue, you may be asked for some of the following information:
WordPress version 5.4.2
Current theme: Kallyas Child Theme (version 4.0.0)
Current plugin: Matomo Analytics – Ethical Stats. Powerful Insights. (version 1.1.2)
PHP version 7.4.7

Error Details
=============
An error of type E_ERROR was caused in line 37 of the file /home/my_site/public_html/wp-content/plugins/matomo/app/vendor/php-di/php-di/src/DI/Definition/Helper/ArrayDefinitionExtensionHelper.php. Error message: Uncaught Error: Class ‘DI\Definition\ArrayDefinitionExtension’ not found in /home/my_site/public_html/wp-content/plugins/matomo/app/vendor/php-di/php-di/src/DI/Definition/Helper/ArrayDefinitionExtensionHelper.php:37
Stack trace:
#0 /home/my_site/public_html/wp-content/plugins/matomo/app/vendor/php-di/php-di/src/DI/Definition/Source/DefinitionArray.php(121): DI\Definition\Helper\ArrayDefinitionExtensionHelper->getDefinition(‘observers.globa…’)
#1 /home/my_site/public_html/wp-content/plugins/matomo/app/vendor/php-di/php-di/src/DI/Definition/Source/DefinitionArray.php(76): DI\Definition\Source\DefinitionArray->castDefinition(Object(DI\Definition\Helper\ArrayDefinitionExtensionHelper), ‘observers.globa…’)
#2 /home/my_site/public_html/wp-content/plugins/matomo/app/vendor/php-di/php-di/src/DI/Definition/Source/DefinitionFile.php(43): DI\Definition\Source\DefinitionArray->getDefinition(‘observers.globa…’)
#3 /home/my_site/public_html/wp-content/plugins/matomo/app/vendor/php-di/php-di/src/DI/Definition/Sou