Create SharePoint multi tenant addin

[stevebeauge]

Hi,

I'm trying to build a multitenant SharePoint addin, but documentation is very hard to find.

1. The very limited SP documentation doesn't mention if ACS auth is mandatory or if AD registered app can be use in SP addin.
2. When I try to use client id/client secret generated from the seller dashboard, I got 401 errors, even though I build a manifest that reuse the client ID and proper host. This works well with appreg.aspx generated client id, but only in originator tenant.
3. How to get actual error messages? Most of time the only observed behavior is a never ending application being installed in the site content

thx