I have created a custom add-on for alert action from Splunk Add-on builder which is working fine on a single search head or any single instance and I am able to see the the global parameters but when I am trying to push this package to the Search-Head cluster, it is unable to load those parameters like proxy details, username, password, etc. on configuration page.
ServiceNow Addon is built by Add-on Builder? Oh I don't know that.
Basically we may need to do sth manually, for example, install this addon on all SH, sync some conf files and KVStore cross all SH, etc.
May I ask what's the error you found from browser console and backend logs?