Error 0x80EE001C

Value: -2131886052 | 0x80EE001C | 2163081244

What does it mean ?

RTC_E_SIP_SSL_TUNNEL_FAILED  
Cannot establish SSL tunnel to Http proxy
Value: 28 | 0x001C | 0b0000000000011100

Where does it come from ?

FACILITY_RTC_INTERFACE  
RTC - Real-time Communications
Value: 238 | 0x0EE | 0b11101110

Other Errors for FACILITY_RTC_INTERFACE