0x000021BB

ERROR_DS_FLAT_NAME_EXISTS_IN_FOREST

The flat name of the trusted domain already exists in the forest.

win32decimal 8635

Matched as: the code as given (hex)

Log a case with no specific solution

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Source: System Error Codes (8200-8999) - Win32 apps · CC BY 4.0 · wording unchanged, formatting adapted for this site · retrieved 2026-10-09