diff --git a/backend/src/main/java/com/mailserver/config/SecurityConfig.java b/backend/src/main/java/com/mailserver/config/SecurityConfig.java
index f05809b..75d9f82 100644
--- a/backend/src/main/java/com/mailserver/config/SecurityConfig.java
+++ b/backend/src/main/java/com/mailserver/config/SecurityConfig.java
@@ -2,11 +2,13 @@ package com.mailserver.config;
 
 import com.mailserver.security.JwtAuthenticationFilter;
 import org.springframework.context.annotation.Bean;
+import org.springframework.http.HttpStatus;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.security.config.annotation.web.reactive.EnableWebFluxSecurity;
 import org.springframework.security.config.web.server.SecurityWebFiltersOrder;
 import org.springframework.security.config.web.server.ServerHttpSecurity;
 import org.springframework.security.web.server.SecurityWebFilterChain;
+import org.springframework.security.web.server.authentication.HttpStatusServerEntryPoint;
 import org.springframework.web.cors.CorsConfiguration;
 import org.springframework.web.cors.reactive.CorsConfigurationSource;
 import org.springframework.web.cors.reactive.UrlBasedCorsConfigurationSource;
@@ -42,6 +44,11 @@ public class SecurityConfig {
     public SecurityWebFilterChain filterChain(ServerHttpSecurity http) {
         http
             .csrf(ServerHttpSecurity.CsrfSpec::disable)
+            // JWT only: without this an API call with no token gets 401 + "WWW-Authenticate: Basic",
+            // and the browser shows its own login popup where our mailbox password does not work
+            .httpBasic(ServerHttpSecurity.HttpBasicSpec::disable)
+            .formLogin(ServerHttpSecurity.FormLoginSpec::disable)
+            .exceptionHandling(e -> e.authenticationEntryPoint(new HttpStatusServerEntryPoint(HttpStatus.UNAUTHORIZED)))
             .cors(cors -> cors.configurationSource(corsConfigurationSource()))
             .authorizeExchange(exchange -> exchange
                 .pathMatchers("/api/login", "/api/register", "/actuator/health").permitAll()
diff --git a/frontend/src/app/interceptors/auth.interceptor.ts b/frontend/src/app/interceptors/auth.interceptor.ts
index c7a2330..3300264 100644
--- a/frontend/src/app/interceptors/auth.interceptor.ts
+++ b/frontend/src/app/interceptors/auth.interceptor.ts
@@ -1,16 +1,22 @@
-import { HttpInterceptorFn, HttpRequest, HttpHandlerFn } from '@angular/common/http';
+import { HttpErrorResponse, HttpInterceptorFn, HttpRequest, HttpHandlerFn } from '@angular/common/http';
+import { inject } from '@angular/core';
+import { Router } from '@angular/router';
+import { catchError, throwError } from 'rxjs';
 
 export const authInterceptor: HttpInterceptorFn = (req: HttpRequest<unknown>, next: HttpHandlerFn) => {
+  const router = inject(Router);
   const token = localStorage.getItem('token');
-  
-  if (token) {
-    const cloned = req.clone({
-      setHeaders: {
-        Authorization: `Bearer ${token}`
+  const request = token ? req.clone({ setHeaders: { Authorization: `Bearer ${token}` } }) : req;
+
+  return next(request).pipe(
+    catchError((error: unknown) => {
+      // not logged in or the token expired → to the login form
+      if (error instanceof HttpErrorResponse && error.status === 401 && !req.url.endsWith('/login')) {
+        localStorage.removeItem('token');
+        localStorage.removeItem('email');
+        router.navigate(['/login']);
       }
-    });
-    return next(cloned);
-  }
-  
-  return next(req);
+      return throwError(() => error);
+    })
+  );
 };