Hi,

Use t-call options to disable header and footer

Instead of commenting out the external layout, pass these context variables when calling it:

<t t-call="web.external_layout">

    <t t-set="no_header" t-value="True"/>

    <t t-set="no_footer" t-value="True"/>

    <!-- Your report content here -->

</t>

no_header and no_footer are respected by web.external_layout template, and will safely hide header/footer while keeping the layout intact.

Hope it helps.