How to debug the connection issue to integrate with external system using connector in OM ?

Summary:

I would like to test the feature of integrate with external system from order management extension.

I have follow the manual to setup the connection, but seems cannot touch the target system endpoint

Here is the setting :

I would like to ask :

• is there any thing I missed to setup ? or any wrong configuration ?
• is there any way to get the respond information (eg. http code) so that I can debug the connection ?

Thanks