Frappe Realtime Notifications Problem

Hello Team,

I want to publish real-time notification to user when visitor doc voucher is saved. I have put below code on validate method but notification is not published. Help would be appreciate. I am working on production environment.

user_list = [‘’,‘Administrator’,‘’]
for u in user_list:
frappe.publish_realtime(event=‘eval_js’, message=‘Hello’, user=u)

I have replace eval_js to msgprint and now it’s working.

This is not working in Frappe Cloud Hosted Site …why?