Are you logged into Zapier with the same id you’re developing with, or did you add yourself as an admin or invited user for that app?  

I had a quick look under the developer account you are posting here with and I do see a couple of connections.  If this continues to be a blocker, I’d open an issue at contact@zapier.com where they can look into your account and logs and help find the problem.

Thanks for response.

I was doing it wrong, I have custom integration and I was adding connection in All app, may be that’s why it was not working. Now I’m able to add connection using custom integration tab.