Error 0x80045092

Value: -2147200878 | 0x80045092 | 2147766418

What does it mean ?

SPERR_SISR_MIXED_NOT_ALLOWED  
Mixed content is not allowed at the top level.
Value: 20626 | 0x5092 | 0b0101000010010010

Where does it come from ?

FACILITY_ITF  
COM/OLE Interface management. FACILITY_ITF is designated for user-defined error codes returned from interface methods
Value: 4 | 0x004 | 0b00000100

StackOverflow

Other Errors for FACILITY_ITF