Steps to reproduce:

1. Use Zabbix server 4.4.0alpha1 or alpha2 (zabbix_server (Zabbix) 4.4.0alpha2 Revision 36f514195c 19 August 2019, compilation time: Aug 15 2019 10:07:23)

1. 1. Debian 10 server
   2. Use repo deb http://repo.zabbix.com/zabbix/4.3/debian buster main
2. Create a new web-scenario under a host.

Result:
The newly create web-scenario does not start to monitor. An older web-scenario created under Zabbix 3.x is still working but newly creates ones don't start monitoring. The "Web monitoring" widget in the Dashboard shows status 'Unknown'  for these broken web-scenario's.

The zabbix_server.log doesn't show any relevant information.