I had an issue where Skype for Business was not showing missed or outbound calls. The environment was an On-Prem Skype for Business server with AzureAD Connect enabled.
Various articles online all state various reasons for why this might occur but none of them mentioned this cause, which is why I’m posting on this.
The issue for us was caused by a missing email address being populated in the user’s active directory account.
I think back when AzureADConnect used to be DirSync, adding the email address used to be a requirement to allow sync of accounts. As soon as the email address of the user was added, the calls history populated immediately.