When I ran this command: msiexec /I EwsManagedApi.msi addlocal="ExchangeWebServicesApi_Feature, ExchangeWebServicesApi_Gac" I received the following error in the event viewer:
Product: Microsoft Exchange Web Services Managed API 1.2 -- The installer has encountered an unexpected error installing this package. This may indicate a problem with this package. The error code is 2711. The arguments are: ExchangeWebServicesApi_Gac,
Log Name: Application
Source: MsiInstaller
Event ID: 10005
HB SharePoint Administrator