I am attempting to create a popup marker for my website. The popups work fine when using codepen: https://codepen.io/awd1236/pen/GROVKdm

For some reason when importing the EXACT SAME CODE in the EXACT SAME format I recieve this error:

Fatal error: Uncaught --> Smarty Compiler: Syntax error in template "file:/var/www/vhosts/secretwebsitedomain/subdomains/secretwebsitedomain/httpdocs/views/pages/map.tpl" on line 60 "<h3>${feature.properties.title}</h3><p>${feature.properties.description}</p>" - Unexpected ".", expected one of: "}" <-- thrown in /var/www/vhosts/secretwebsitedomain/subdomains/secretwebsitedomain/httpdocs/vendor/smarty/smarty/libs/sysplugins/smarty_internal_templatecompilerbase.php on line 60.

This is the initial code that works on codepen:

new mapboxgl.Marker(el)
.setLngLat(feature.geometry.coordinates)
.setPopup(
new mapboxgl.Popup({ offset: 25 }) // add popups
.setHTML(
`<h3>${feature.properties.title}</h3><p>${feature.properties.description}</p>`
)
)
.addTo(map);
}

This is the line that is causing the error (line 60) in the smarty.../sysplugins/ folder:

I am unsure what I can do to fix this error.