Context: WordPress (5.8.3 or 5.9) connection to Matomo on Premise (v4.6.2) with WP-Matomo Integration (v1.0.26).
For some reason, there is a 500 error since last night at 0h05 while nothing has been updated at that time.
The WordPress debug indicates the following information:
PHP Fatal error: Declaration of Piwik\Plugins\Monolog\Handler\WebNotificationHandler::write(array $record) must be compatible with Monolog\Handler\AbstractProcessingHandler::write(array $record): void in /home/user1/website.com/matomo/plugins/Monolog/Handler/WebNotificationHandler.php on line 34
Matomo is used on a bunch of WordPress sites that I manage. No other site has this problem.