Error 0x80EF0191

Value: -2131820143 | 0x80EF0191 | 2163147153

What does it mean ?

RTC_E_STATUS_CLIENT_UNAUTHORIZED  
Unauthorized
Value: 401 | 0x0191 | 0b0000000110010001

Where does it come from ?

FACILITY_SIP_STATUS_CODE  
SIP - Session Initiation Protocol (VoIP)
Value: 239 | 0x0EF | 0b11101111

Other Errors for FACILITY_SIP_STATUS_CODE