Brf form post meta not working for background

I’m using {brf_post_meta:imagefieldname:{url_parameter:id}} to have image url act as value for background but no background is showing , when I inspect code, the url value is no where to be found

When I use {brf_post_meta:imagefieldname:{url_parameter:id}} else where I can see url

{brf_post_thumbnail_url:post_id} is already in use and it shows featured image only i think

by the way I also created a hidden field to display image url value and try to use {brf_form_live_value:field_id} to show hidden field value but still nothing