Answers.Body: <p>Never too late to answer (but fixed weeks ago), apparently our host performed an update on the server that activated several new mod_security rules. One of them was affecting the login.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-08-05T15:40:54.843Z
Answers.LastActivityDate: 2019-08-05T15:40:54.843Z
Answers.UserDisplayName: Maxime Lafrenière
Answers.Body: <blockquote>
    <p>Template not found: 403.shtml</p>
  </blockquote>
  
  <p><code>403.shtml</code> isn't a file that Craft ships with, so most likely it's your web server injecting that into the response of the login POST request for some reason.</p>
  
  <p>Maybe you've got mod_security or Suhosin installed on that server and it's tripping up one of their security rules, for example.</p>
  
  <p>Regardless, it's something you should probably contact your host with as they'll likely be able to help you debug it better.</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-06-25T22:22:45.377Z
Answers.LastActivityDate: 2019-06-25T22:22:45.377Z
Answers.UserDisplayName: Brad Bell
Body: <p>Can't login in my staging env since last full plugins/craft update (still able to in my local env).</p>
  
  <p><strong>I already...</strong></p>
  
  <ol>
  <li>Remove my <code>composer.lock</code> and <code>/vendor</code> files and re-install all components</li>
  <li>Rename/delete the <code>/web/cpresources</code> directory</li>
  <li>Flush all caches throught CLI command</li>
  <li>Try to login in Private mode and other browsers</li>
  </ol>
  
  <p>And still, I got this as a response :</p>
  
  <pre><code>{"error":"Template not found: 403.shtml"}
  </code></pre>
  
  <p><strong>Here's the trace</strong></p>
  
  <p><a href="https://pastebin.com/63NA1XQy" rel="nofollow noreferrer">https://pastebin.com/63NA1XQy</a></p>
  
  <p><strong>Here's the composer.json</strong></p>
  
  <pre><code>{
      "require": {
          "craftcms/cms": "3.1.31",
          "vlucas/phpdotenv": "^2.4.0",
          "spicyweb/craft-neo": "2.3.5",
          "anubarak/craft-relabel": "1.3.1",
          "ether/seo": "3.5.4",
          "verbb/super-table": "2.1.20",
          "verbb/expanded-singles": "1.0.7",
          "verbb/field-manager": "2.1.0",
          "craftcms/redactor": "2.3.3.2",
          "verbb/navigation": "1.1.12",
          "pennebaker/craft-architect": "2.3.1",
          "marionnewlevant/twig-perversion": "2.1.0",
          "clubstudioltd/craft-inline-svg": "v0.1.1",
          "marionnewlevant/snitch": "3.0.0",
          "selvinortiz/patrol": "3.1.3",
          "fruitstudios/linkit": "1.1.11",
          "craftcms/contact-form": "2.2.5",
          "tomodomo/twig-pluralize-extension": "^2.0",
          "verbb/icon-picker": "^1.0",
          "craftcms/element-api": "^2.5"
      },
      "config": {
          "optimize-autoloader": true,
          "platform": {
              "php": "7.2.10"
          }
      },
      "autoload": {
          "psr-4": {
              "modules\\businesslogic\\": "modules/businesslogic/src/"
          }
        },
      "scripts": {
          "post-root-package-install": [
              "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
          ]
      }
  }
  
  </code></pre>
  
  <p>–</p>
  
  <p><strong>EDIT</strong>: Apparently this issue happens on all our Craft sites (both 2 and 3) on our server, will update as soon as I found out more</p>
  
Tags: <craft3>
Title: Got 404 on login attempt (Template not found: actions/users/login)
ThreadText: # Got 404 on login attempt (Template not found: actions/users/login)
  
  (Asked by: username_0 on 2019-06-25)
  
  Can't login in my staging env since last full plugins/craft update (still able to in my local env).
  
  **I already...**
  
  1. Remove my `composer.lock` and `/vendor` files and re-install all components
  2. Rename/delete the `/web/cpresources` directory
  3. Flush all caches throught CLI command
  4. Try to login in Private mode and other browsers
  
  And still, I got this as a response :
  
  ```
  {"error":"Template not found: 403.shtml"}
  
  ```
  
  **Here's the trace**
  
  <https://pastebin.com/63NA1XQy>
  
  **Here's the composer.json**
  
  ```
  {
      "require": {
          "craftcms/cms": "3.1.31",
          "vlucas/phpdotenv": "^2.4.0",
          "spicyweb/craft-neo": "2.3.5",
          "anubarak/craft-relabel": "1.3.1",
          "ether/seo": "3.5.4",
          "verbb/super-table": "2.1.20",
          "verbb/expanded-singles": "1.0.7",
          "verbb/field-manager": "2.1.0",
          "craftcms/redactor": "2.3.3.2",
          "verbb/navigation": "1.1.12",
          "pennebaker/craft-architect": "2.3.1",
          "marionnewlevant/twig-perversion": "2.1.0",
          "clubstudioltd/craft-inline-svg": "v0.1.1",
          "marionnewlevant/snitch": "3.0.0",
          "selvinortiz/patrol": "3.1.3",
          "fruitstudios/linkit": "1.1.11",
          "craftcms/contact-form": "2.2.5",
          "tomodomo/twig-pluralize-extension": "^2.0",
          "verbb/icon-picker": "^1.0",
          "craftcms/element-api": "^2.5"
      },
      "config": {
          "optimize-autoloader": true,
          "platform": {
              "php": "7.2.10"
          }
      },
      "autoload": {
          "psr-4": {
              "modules\\businesslogic\\": "modules/businesslogic/src/"
          }
        },
      "scripts": {
          "post-root-package-install": [
              "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
          ]
      }
  }
  
  ```
  
  –
  
  **EDIT**: Apparently this issue happens on all our Craft sites (both 2 and 3) on our server, will update as soon as I found out more
  
  **Tags:** craft3
  
  
  ---
  
  ## 2 answers
  
  ### Answer by username_0 on 2019-08-05. Score: 1 | Accepted answer
  
  Never too late to answer (but fixed weeks ago), apparently our host performed an update on the server that activated several new mod\_security rules. One of them was affecting the login.
  
  
  ---
  
  ### Answer by username_1 on 2019-06-25. Score: 0
  
  > Template not found: 403.shtml
  
  `403.shtml` isn't a file that Craft ships with, so most likely it's your web server injecting that into the response of the login POST request for some reason.
  
  Maybe you've got mod\_security or Suhosin installed on that server and it's tripping up one of their security rules, for example.
  
  Regardless, it's something you should probably contact your host with as they'll likely be able to help you debug it better.
  
  
  ---
  
  