Deprecated function: Drupal\nagios\Controller\StatuspageController::setNagiosStatusConstants(): Implicitly marking parameter $config as nullable is deprecated, the explicit nullable type must be used instead in include() (
Install the nagios module
Set error logging to an appropriate level
View the watchdog.
Investigating the code fixes.
These are minor issues. Annoying if you are trying to look for other issues in code, but don't affect a lot of people.
Active
1.24
Code
Issue #3528298: Deprecated function in the nagios module