Steps to reproduce:

1. Create an HTTP Agent Item.
2. Add a JavaScript preprocessing step that does an HTTP get to an endpoint that can only resolve within the proxy network (OpenShift in my case).
3. Get Value And Test.
4. The initial HTTP Agent works and can talk to the OpenShift endpoint from the proxy.
5. The preprocessing step using the obtained token does not work with the error "Couldn't resolve host name"

There has been a bug reported ZBX-24800 called "Remote command not executed on proxy but on server" which sounds like almost the same problem but that has been fixed in 7.0.3rc1, this however has not solved it as I upgraded after reading this bug and fix.

Result:
Please see the screen shot attached for the item test output.
Expected:
I would expect that both the HTTP agent and JavaScript preprocessing step be initiated from the proxy on site instead of the main Zabbix instance which would then allow the DNS to resolve in the preprocessing step as well as the HTTP agent request.