Hi Guys,

We have an existing K2 Five (5.0) environment On Prem working with our On Prem SharePoint 2016. We’ve now migrated our Exchange and SharePoint operations to Office 365 (SharePoint Online). I have created a new App Catalogue in SharePoint Online and added the K2 Five app successfully from the Microsoft App Store. 

Now, when I try to Register K2 Five the following happens: 
 

1. I enter our K2 server address - it is already publicly accessible and behind a https://
2. It shows ‘verifying relaying’
3. Asks me to login to Office 365 - I use the O365 Admin account
4. I get a Microsoft Prompt to Allow K2 for Office 365 a bunch of permissions
5. Trust.k2.com comes up verifying permissions and then automatically goes to
6. App Only configured for Tenant with a bunch of permissions automatically
7. and then it tries to go back to the App address of the K2 app and I get a 500 Internal Server Error

Not sure what to do to get this to register properly - did I miss something?

Any ideas and suggestions appreciated ;)