diff --git a/apps/coordinator-api/src/app/exceptions.py b/apps/coordinator-api/src/app/exceptions.py
index 40c6e200..4f67ef64 100755
--- a/apps/coordinator-api/src/app/exceptions.py
+++ b/apps/coordinator-api/src/app/exceptions.py
@@ -22,7 +22,7 @@ class ErrorResponse(BaseModel):
     """Standardized error response for all API errors."""
 
     error: dict[str, Any] = Field(..., description="Error information")
-    timestamp: str = Field(default_factory=lambda: datetime.now(datetime.UTC).isoformat() + "Z")
+    timestamp: str = Field(default_factory=lambda: datetime.now(UTC).isoformat() + "Z")
     request_id: str | None = Field(None, description="Request ID for tracing")
 
     class Config: