Devon,
Thank you very much for the info.
I should have checked the documentation more carefully.
After I submitted my posting, I've gone through the steps you've described above and it worked.
I was able to add survey123.com to App Launcher. And I am able to navigate to survey123.com with my portal url initialized.
Now, when I try to create a survey using "Survey Connect", it creates feature service on portal but it doesn't allow me to publish the form. And I am getting "Error 400".
Do you know what this error referring to?
Can you tell me what other steps I need to take so my survey 123 mobile app can access my portal resource?
Do I still need to setup portal with reverse proxy or are there ways without having to setup reverse proxy?
thanks for your time
Don Kang