Sorry for the delayed reply on this. I did not get a notification that you had replied. Hopefully you didn’t give up.
The main problem is that ACF stores uploaded image field as the image ID value. The plugin that you’re using expects the database to hold a URL and it’s finding an ID instead.
There are 2 choices, use a text field or a URL field and then find and paste in the URL or some coding.
The coding involved is what I said above, set up your image field to return the URL of the image. In you function.php file create a save post action function. In this function you get the field from the ACF image field.
$srch = get_field('image_field_name')
Then insert the image URL into another field
update_post_meta($post_id, 'image_field_name_for_plugin', $value);
Then you can use the new field name for the plugin that needs the URL of the image.
