Outlook 2016 disables Add-In on Startup and changes the LoadBehavior value in registry

We have a custom outlook Add-In which works fine in Outlook 2010. But in Outlook 2016 the add-in gets disabled when outlook is restarted.

Observations:

1. I can see that in Windows registry, LoadBehavior value get changed from 3 to 2, which causes the add-in to get disabled. I tried changing the value to 3 manually but it changes back to 2 every time I restart the Outlook.

2. In my Add-in Code, at Startup event while creating outlook object following exception occures.

Retrieving the COM class factory for component with CLSID {0006F03A-0000-0000-C000-000000000046} failed due to the following error:

8000ffff catastrophic failure (Exception from HRESULT : 0x8000FFFF (E_UNEXPECTED)

Please suggest a way forward to handle this situation.