Error 0x8802D007

Value: -2013081593 | 0x8802D007 | 2281885703

What does it mean ?

E_SYNCENGINE_PROXY_AUTHENTICATION_REQUIRED  
The sync engine needs to authenticate with a proxy server.
Value: 53255 | 0xD007 | 0b1101000000000111

Where does it come from ?

FACILITY_SYNCENGINE  
Synchronization Engine
Value: 2050 | 0x802 | 0b100000000010

Other Errors for FACILITY_SYNCENGINE