diff --git a/app/lib/auth-middlewares/convert-legacy-user.ts b/app/lib/auth-middlewares/convert-legacy-user.ts
index e590b7e6..28a602f5 100644
--- a/app/lib/auth-middlewares/convert-legacy-user.ts
+++ b/app/lib/auth-middlewares/convert-legacy-user.ts
@@ -3,6 +3,7 @@ import { and, eq, ne } from "drizzle-orm";
 import { db } from "~/server/db/db";
 import { account, usersTable } from "~/server/db/schema";
 import type { AuthMiddlewareContext } from "../auth";
+import { UnauthorizedError } from "http-errors-enhanced";
 
 export const convertLegacyUserOnFirstLogin = async (ctx: AuthMiddlewareContext) => {
 	const { path, body } = ctx;
@@ -45,7 +46,7 @@ export const convertLegacyUserOnFirstLogin = async (ctx: AuthMiddlewareContext)
 				});
 			});
 		} else {
-			throw new Error("Invalid credentials");
+			throw new UnauthorizedError("Invalid credentials");
 		}
 	}
 };
diff --git a/app/lib/auth-middlewares/only-one-user.ts b/app/lib/auth-middlewares/only-one-user.ts
index 0fbc237e..af5e1a82 100644
--- a/app/lib/auth-middlewares/only-one-user.ts
+++ b/app/lib/auth-middlewares/only-one-user.ts
@@ -3,6 +3,7 @@ import type { AuthMiddlewareContext } from "../auth";
 import { logger } from "~/server/utils/logger";
 import { eq } from "drizzle-orm";
 import { appMetadataTable } from "~/server/db/schema";
+import { ForbiddenError } from "http-errors-enhanced";
 
 export const REGISTRATION_DISABLED_KEY = "registrationsDisabled";
 
@@ -20,6 +21,6 @@ export const ensureOnlyOneUser = async (ctx: AuthMiddlewareContext) => {
 
 	if (result?.value === "true" && existingUser) {
 		logger.info("User registration attempt blocked: registrations are disabled.");
-		throw new Error("User registrations are currently disabled. Please contact an administrator for access.");
+		throw new ForbiddenError("User registrations are currently disabled. Please contact an administrator for access.");
 	}
 };
diff --git a/app/lib/auth.ts b/app/lib/auth.ts
index da324aec..56b5f99a 100644
--- a/app/lib/auth.ts
+++ b/app/lib/auth.ts
@@ -7,6 +7,7 @@ import {
 } from "better-auth";
 import { drizzleAdapter } from "better-auth/adapters/drizzle";
 import { admin, createAuthMiddleware, twoFactor, username, organization } from "better-auth/plugins";
+import { UnauthorizedError } from "http-errors-enhanced";
 import { convertLegacyUserOnFirstLogin } from "./auth-middlewares/convert-legacy-user";
 import { eq } from "drizzle-orm";
 import { config } from "../server/core/config";
@@ -21,6 +22,9 @@ const createBetterAuth = (secret: string) =>
 	betterAuth({
 		secret,
 		trustedOrigins: config.trustedOrigins ?? ["*"],
+		onAPIError: {
+			throw: true,
+		},
 		hooks: {
 			before: createAuthMiddleware(async (ctx) => {
 				await ensureOnlyOneUser(ctx);
@@ -81,7 +85,7 @@ const createBetterAuth = (secret: string) =>
 						});
 
 						if (!orgMembership) {
-							throw new Error("User does not belong to any organization");
+							throw new UnauthorizedError("User does not belong to any organization");
 						}
 
 						return {