Steps to reproduce:

1. Create a connector with URL that doesn't respond with a JSON
   2. Try to stop the server:

     3365:20231109:172819.008 [2] thread stopped [preprocessing worker #2]
     3376:20231109:172819.009 syncing history data in progress...
     3376:20231109:172819.009 syncing history data done
     3421:20231109:172839.010 cannot retrieve error from "http://localhost/zabbix/in": cannot parse as a valid JSON object
   ...
     3421:20231109:172839.010 cannot send data to "http://localhost/zabbix/in": Response code "404" did not match any of the required status codes "200"
   ...
     3421:20231109:172919.017 cannot retrieve error from "http://localhost/zabbix/in": cannot parse as a valid JSON object: 
   ...
     3421:20231109:172919.017 cannot send data to "http://localhost/zabbix/in": Response code "404" did not match any of the required status codes "200"
     3421:20231109:172959.023 cannot retrieve error from "http://localhost/zabbix/in": cannot parse as a valid JSON object: 
   

   Most proc titles say "[terminated]" (pollers, etc) but alerters and connectors do not.