You get these alerts due to logs in your application being logged as "Critical". From our documentation: 

If any logging is done on the CRITICAL level, the alerts status always directly switches to Critical. The critical log message counter will only be reset when restarting the application process.

Thus, if you get such an alert, you can take a look at your logs and look for the logs logged at the “Critical” level. Without those logs, it is impossible for us to know what’s wrong. We can help you investigate if you share those logs :)