How to toubleshoot configuration of MS Bot Framewo

Question

We are having a bot based on MS Bot Framework. It communicates as desired via DirectLine, Email, Facebook Messenger, Skype and WebChat.

We tried also to configure Skype for Business (hereinafter SfB) but without success.

1) We have enabled

2) Tenant Administrator of our SfB has followed instructions: "Learn how" using brand new user id. Our SfB comes with Office 365 subscription. The result in powershell looked similar to:

RunspaceId     : aaaaaaaa-aaaa-1234-1234-1a1111aaaaaa
FriendlyName   : Our-Name 
Id             : bbbbbbbb-bbbb-1234-1234-1b1111bbbbbb
TenantId       : cccccccc-cccc-1234-1234-1c1111cccccc
EndpointType   : Targeted 
SipUri         : sip:[e-mail] 
PhoneNumber    : 
CallbackUri    : 
Ring           : ring2

3) If I send message to chosen user via SfB messenger it allways end up like: And we don't see any trace of SfB conversation in log of our bot.

Could you please recommend what settings of either MS Botframework or our SfB to check? Which logs to examine or enable to find any new clue?