# I can't sent e-mails, I get error code about authentication

**URL:** <https://forum.mautic.org/t/i-cant-sent-e-mails-i-get-error-code-about-authentication/36555>\
**Category:** Product Support\
**Created:** [September 17, 2025, 9:38am UTC](https://forum.mautic.org/t/i-cant-sent-e-mails-i-get-error-code-about-authentication/36555 "2025-09-17T09:38:58Z")\
**Posts on this page:** 3\
**Page:** 1

<div class="post-metadata">

**Author:** ![rowena](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/rowena/32/13489_2.png) [@rowena](https://forum.mautic.org/u/rowena)\
**Post date:** [September 17, 2025, 9:38am UTC](https://forum.mautic.org/t/i-cant-sent-e-mails-i-get-error-code-about-authentication/36555/1 "2025-09-17T09:38:58Z")

</div>

**Your software**  
My Mautic version is: v6.0.4  
My PHP version is: 8.3.6  
My Database type and version is: Doctrine driver pdo\_mysql, 10.11.13-MariaDB-0ubuntu0.24.04.1

**Your problem**  
My problem is: I cannot sent e-mails, I get error codes but can’t seem to fix it by myself. What an I missing here?

These errors are showing in the log:  
When I want to send a custom e-mail: Failed to send to xxxx@xxxxx.nl: Failed to authenticate on SMTP server with username “xxxx@xxxxxx.nl” using the following authenticators: “LOGIN”, “PLAIN”. Authenticator “LOGIN” returned “Expected response code “235” but got code “535”, with message “535 5.7.8 Error: authentication failed: UGFzc3dvcmQ6”.”. Authenticator “PLAIN” returned “Expected response code “235” but got code “535”, with message “535 5.7.8 Error: authentication failed: UGFzc3dvcmQ6”.”.

**And the log:**  
[2025-09-17T00:02:27.369214+00:00] mautic.ERROR: Uncaught PHP Exception Symfony\Component\HttpKernel\Exception\BadRequestHttpException: “Untrusted Host “213.199.63.178”.” at /var/www/mautic-app/vendor/symfony/http-kernel/HttpKernel.php line 83 {“exception”:“[object] (Symfony\\Component\\HttpKernel\\Exception\\BadRequestHttpException(code: 0): Untrusted Host \“213.199.63.178\”. at /var/www/mautic-app/vendor/symfony/http-kernel/HttpKernel.php:83)\n[previous exception] [object] (Symfony\\Component\\HttpFoundation\\Exception\\SuspiciousOperationException(code: 0): Untrusted Host \“213.199.63.178\”. at /var/www/mautic-app/vendor/symfony/http-foundation/Request.php:1186)”} {“hostname”:“vmd176712”,“pid”:1740045}  
[2025-09-17T00:02:27.430441+00:00] mautic.CRITICAL: Exception thrown when handling an exception (Twig\Error\RuntimeError: An exception has been thrown during the rendering of a template (“There is currently no session available.”). at /var/www/mautic-app/app/bundles/CoreBundle/Resources/views/Default/script.html.twig line 9) {“exception”:“[object] (Twig\\Error\\RuntimeError(code: 0): An exception has been thrown during the rendering of a template (\“There is currently no session available.\”). at /var/www/mautic-app/app/bundles/CoreBundle/Resources/views/Default/script.html.twig:9)\n[previous exception] [object] (Symfony\\Component\\HttpFoundation\\Exception\\SessionNotFoundException(code: 0): There is currently no session available. at /var/www/mautic-app/vendor/symfony/http-foundation/RequestStack.php:107)”} {“hostname”:“vmd176712”,“pid”:1740045}  
[2025-09-17T00:02:27.447903+00:00] mautic.ERROR: Twig\Error\RuntimeError: An exception has been thrown during the rendering of a template (“There is currently no session available.”). - in file /var/www/mautic-app/app/bundles/CoreBundle/Resources/views/Default/script.html.twig - at line 9 {“hostname”:“vmd176712”,“pid”:1740045}

Steps I have tried to fix the problem: change the mail adress from sender and check if DSN test mail works, and it does.

 ![image](https://us1.discourse-cdn.com/flex020/uploads/mautic/original/2X/f/f058ecc9664f578cd21f9dc6f106b2b0511f66f8.png)

 ![image](https://us1.discourse-cdn.com/flex020/uploads/mautic/original/2X/e/e89b70f5054beb53a7af0e85b2b18ae591c805de.png)

---

<div class="post-metadata">

**Author:** ![rowena](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/rowena/32/13489_2.png) [@rowena](https://forum.mautic.org/u/rowena)\
**Post date:** [September 17, 2025, 12:35pm UTC](https://forum.mautic.org/t/i-cant-sent-e-mails-i-get-error-code-about-authentication/36555/2 "2025-09-17T12:35:57Z")

</div>

edit: I think we’ve solved it.

---

<div class="post-metadata">

**Author:** ![danish](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/danish/32/14540_2.png) [@danish](https://forum.mautic.org/u/danish)\
**Post date:** [October 29, 2025, 6:25am UTC](https://forum.mautic.org/t/i-cant-sent-e-mails-i-get-error-code-about-authentication/36555/3 "2025-10-29T06:25:08Z")

</div>

how ? can you kinldy tell me i also face exactly the same issue 😐