# Strange Link Additional Code **URL:** \ **Category:** Product Support\ **Created:** [April 14, 2024, 2:34pm UTC](https://forum.mautic.org/t/strange-link-additional-code/31674 "2024-04-14T14:34:57Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![taxi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/taxi/32/522_2.png) [@taxi](https://forum.mautic.org/u/taxi)\ **Post date:** [April 14, 2024, 2:34pm UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/1 "2024-04-14T14:34:57Z")
I made an email with a button. The link is [https://website.com/thank-you](https://website.com/thank-you) When I’m pressing the button in the email the link has changed as follows: [https://website.com/thank-you?ct=YTo1OntzOjY6InNvdXJjZSI7YToyOntpOjA7czoxNDoiY2FtcGFpZ24uZXZlbnQiO2k6MTtpOjI1Nzt9czo1OiJlbWFpbCI7aToxMjc7czo0OiJzdGF0IjtzOjIyOiI2NjFiZTg2ZjRlZDA3MDY1NTE0MDgyIjtzOjQ6ImxlYWQiO3M6NToiMjMwNTciO3M6NzoiY2hhbm5lbCI7YToxOntzOjU6ImVtYWlsIjtpOjEyNzt9fQ%3D%3D](https://website.com/thank-you?ct=YTo1OntzOjY6InNvdXJjZSI7YToyOntpOjA7czoxNDoiY2FtcGFpZ24uZXZlbnQiO2k6MTtpOjI1Nzt9czo1OiJlbWFpbCI7aToxMjc7czo0OiJzdGF0IjtzOjIyOiI2NjFiZTg2ZjRlZDA3MDY1NTE0MDgyIjtzOjQ6ImxlYWQiO3M6NToiMjMwNTciO3M6NzoiY2hhbm5lbCI7YToxOntzOjU6ImVtYWlsIjtpOjEyNzt9fQ%3D%3D) Where does this oh so long string come from? It is a mjml template. **Your software** My Mautic version is: 5.0.4 My PHP version is: 8.1.27 My Database type and version is: ---
**Author:** ![joeyk](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/joeyk/32/11164_2.png) [@joeyk](https://forum.mautic.org/u/joeyk)\ **Post date:** [April 15, 2024, 12:08pm UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/2 "2024-04-15T12:08:29Z")
Hello, seems, that this is added by your smtp provider. Which one do you use? Maybe Sendgrid? Also: is click tracking turned on your your SMTP provide’s panel? ---
**Author:** ![taxi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/taxi/32/522_2.png) [@taxi](https://forum.mautic.org/u/taxi)\ **Post date:** [April 16, 2024, 7:07am UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/3 "2024-04-16T07:07:21Z")
Hello Joey I’m using Postfix on my own mail server. What’s the advantage of sending via a SMTP provider? Is it that my server does not land on a black list as SPAM mail server, when sending several thousand emails per day? Append tracking pixel into email body ? Is 'On" which should be okay, in order to track opening of mail. I just checked another old campaign, which worked perfectly with Mautic 4. And now there is also added this strange code. ---
**Author:** ![taxi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/taxi/32/522_2.png) [@taxi](https://forum.mautic.org/u/taxi)\ **Post date:** [September 30, 2024, 1:36pm UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/4 "2024-09-30T13:36:15Z")
Hello Joey, When I click on the button in the email sent by mautic, it shows the link with the added ct=Something which results in a 404 error. If I’m removing the ct=“String” from the end of the link, the wanted page is shown. Any advice or help on this issue? Kind regards Christian ---
**Author:** ![joeyk](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/joeyk/32/11164_2.png) [@joeyk](https://forum.mautic.org/u/joeyk)\ **Post date:** [September 30, 2024, 2:29pm UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/5 "2024-09-30T14:29:02Z")
Yes, the SMTP is needed to have a pre-warmed IP, so you don’t worry about reputation. You can also use your own SMTP via Postfix, that is also perfect. The more emails you send the harder it is to keep a good reputation. I’m not sure why that CT= is there I’m almost sure it’s coming from your code somehow. This is not something Mautic adds. Where do you read your emails? maybe that software is adding it? For example - did you turn on any Click Tracking and maybe Open tracking at your SMTP? ---
**Author:** ![taxi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/taxi/32/522_2.png) [@taxi](https://forum.mautic.org/u/taxi)\ **Post date:** [October 1, 2024, 7:20am UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/6 "2024-10-01T07:20:28Z")
At the moment I’m not sending many mails. I have to inform myself on this as well, because I thought that when I have my own mail server I can send as much as I want, without any problems. You mean that the receiver servers put my mail server onto a blacklist? This is the matter of reputation and why using SendGrid? Now, the link on the confirmation button in my Mautic email ist “[https://website1.com/thank-you](https://website1.com/thank-you)”. This is also shown correctly in the preview of while editing the email with Mautic. My Mautic URL is [webxyz.com](http://webxyz.com). When the email arrives in my inbox the link is transformed to "https://url\_of\_mautic\_installation.com/thank-you?ct=YTo1OntzOjY6InNvdXJjZSI7YTo3D%3D […] This is definitely not transformed by my Postfix installation. Any other hint or avice? ---
**Author:** ![taxi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/taxi/32/522_2.png) [@taxi](https://forum.mautic.org/u/taxi)\ **Post date:** [October 1, 2024, 8:02am UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/7 "2024-10-01T08:02:09Z")
Another thing I just found out. When I’m sending the email via the “send example” function in Mautic, the email comes with the correct link and domain in my inbox. Only when sending is triggerd by the campaign, the link is transformed to the mautic domain and the ?ct= stuff. ---
**Author:** ![taxi](https://sea2.discourse-cdn.com/flex020/user_avatar/forum.mautic.org/taxi/32/522_2.png) [@taxi](https://forum.mautic.org/u/taxi)\ **Post date:** [October 2, 2024, 10:39am UTC](https://forum.mautic.org/t/strange-link-additional-code/31674/8 "2024-10-02T10:39:35Z")
**Solution found!** The problem was with my Typo3 Installation. Since version 10 a parameter ‘cacheHash’ =\> [‘enforceValidation’ =\> true] was introduced. This does not work with the links put together by Mautic. The parameter has to be ‘cacheHash’ =\> [‘enforceValidation’ =\> false] Thank you all for your patience and help! Christian