Rendering issues while creating the header in a report

Question

I have created a PDF report using these NodeJS libraries:

• node-html-pdf (node-html-pdf
• EJS

I have enabled the footer property in the node-html-pdf options object:

const options = {
    // ... other properties
    header: { "height": "40mm" },
}

The height for the header has been changed with different values, but a fixed/extra height is added. The following image shows the current state:

In the HTML template I have this code:

<div id="pageHeader-first" style="height: 0px !important; visibility: hidden;">Header on first page</div>
    <div id="pageHeader" style="margin-top: 0px; padding-top: 0px; position: absolute; left: 60px;">
        <table border="1" style="width: 900px">
            <tr>
                <td colspan="8">
                    <h4 class="negrilla text-center">Certificate</h4>
                </td>
                <td rowspan="2">
                    <div class="text-center"><img src="https://i.imgur.com/animage.png" width="80px"></div>
                </td>
            </tr>
            <tr>
                <td>Certificate</td>
                <td>:</td>
                <td>000212</td>
                <td colspan="2"></td>
                <td>Date</td>
                <td>:</td>
                <td>21-ene.-2022</td>
            </tr>
        </table>
    </div>

Thanks in advance for your help.