diff --git a/plugins/auth-node/src/proxy/createProxyRouteHandlers.ts b/plugins/auth-node/src/proxy/createProxyRouteHandlers.ts
index 10ad62d2bf..521fe39288 100644
--- a/plugins/auth-node/src/proxy/createProxyRouteHandlers.ts
+++ b/plugins/auth-node/src/proxy/createProxyRouteHandlers.ts
@@ -25,6 +25,7 @@ import {
 } from '../types';
 import { ProxyAuthenticator } from './types';
 import { prepareBackstageIdentityResponse } from '../identity';
+import { NotImplementedError } from '@backstage/errors';
 
 /** @public */
 export interface ProxyAuthRouteHandlersOptions<TResult> {
@@ -47,11 +48,11 @@ export function createProxyAuthRouteHandlers<TResult>(
 
   return {
     async start(): Promise<void> {
-      throw new Error('Not implemented');
+      throw new NotImplementedError('Not implemented');
     },
 
     async frameHandler(): Promise<void> {
-      throw new Error('Not implemented');
+      throw new NotImplementedError('Not implemented');
     },
 
     async refresh(this: never, req: Request, res: Response): Promise<void> {
diff --git a/plugins/auth-node/src/sign-in/createSignInResolverFactory.ts b/plugins/auth-node/src/sign-in/createSignInResolverFactory.ts
index 6379eafd25..0632b704c3 100644
--- a/plugins/auth-node/src/sign-in/createSignInResolverFactory.ts
+++ b/plugins/auth-node/src/sign-in/createSignInResolverFactory.ts
@@ -18,6 +18,7 @@ import { ZodSchema, ZodTypeDef } from 'zod';
 import { SignInResolver } from '../types';
 import zodToJsonSchema from 'zod-to-json-schema';
 import { JsonObject } from '@backstage/types';
+import { InputError } from '@backstage/errors';
 
 /** @public */
 export interface SignInResolverFactory<TAuthResult, TOptions> {
@@ -55,7 +56,7 @@ export function createSignInResolverFactory<
   if (!optionsSchema) {
     return (resolverOptions?: TOptionsInput) => {
       if (resolverOptions) {
-        throw new Error('sign-in resolver does not accept options');
+        throw new InputError('sign-in resolver does not accept options');
       }
       return options.create(undefined as TOptionsOutput);
     };