diff --git a/src/actions/user-actions.ts b/src/actions/user-actions.ts
index ec961ba..d1444e2 100644
--- a/src/actions/user-actions.ts
+++ b/src/actions/user-actions.ts
@@ -51,6 +51,14 @@ export async function rejectUser(
 	const userId = formData.get("userId") as string;
 	const rejection_details = formData.get("rejection_details") as string;
 
+	if (!rejection_details?.trim()) {
+		return {
+			message: "Rejection details are required.",
+			fieldErrors: { rejection_details: ["Rejection details are required."] },
+			payload: formData,
+		};
+	}
+
 	const response = await apiClient.delete(
 		`/api/auth/users/${userId}/reject/`,
 		{ data: { rejection_details } },
@@ -65,17 +73,17 @@ export async function rejectUser(
 		};
 	}
 
-	if (response.status < 200 || response.status >= 300) {
-		const errorData = (response.data ?? {}) as ApiError;
-		throw new Error(
-			errorData.message || errorData.detail || "Failed to reject user",
-		);
-	}
-
 	const error = (response.data ?? {}) as ApiError;
+	const message =
+		error.message || error.detail || "Failed to reject user.";
+	// The backend requires a non-empty reason; surface that as a field error so
+	// the textarea highlights, otherwise just toast the message.
+	const isReasonError = /rejection details/i.test(message);
 	return {
-		message: error.message || error.detail || "An unexpected error occurred.",
-		fieldErrors: {},
+		message,
+		fieldErrors: isReasonError
+			? { rejection_details: [message] }
+			: {},
 		payload: formData,
 	};
 }