> For the complete documentation index, see [llms.txt](https://docs.mailrocket.io/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.mailrocket.io/help-center/troubleshoot-issues/template-mismatch.md).

# Template mismatch

When previewing an email template or sending/scheduling a campaign, Mail Rocket validates the selected template in the background. If any variable in the email template is missing from your contact list, it will display a "Mail Merge Issue - Template Mismatch" warning.

{% hint style="success" %}
If you feel the email template is normal, feel free to continue sending emails.
{% endhint %}

<figure><img src="/files/HGXZbxZhfxSgtL7mLfoz" alt=""><figcaption></figcaption></figure>

### How to fix "Empty variables detected"?

In the above screenshot, empty variable detected is **{{ namp }}.** This means column **"namp"** is missing from your contact list.

The screenshot below shows the initial contact list.

<figure><img src="/files/5NUc6Cox0J5388bhng1y" alt=""><figcaption></figcaption></figure>

Add a column called **"namp"** along with its values as shown in the screenshot below.

<figure><img src="/files/aTJIzpbwrmyB5htIfREB" alt=""><figcaption></figcaption></figure>

After all the columns needed are added, restart Mail Rocket.