If you ever stumbled with question why your markdown email in Laravel doesn't render properly, you have to know - that you need to remove any tabs/spaces before lines, so if you like to press CTRL+ALT+L and format your template pretty, be aware that it will broke your mail template :)
Be sure that your template looks like this.
@component('mail::message')
# Invoice Paid
Your invoice has been paid!
@component('mail::button', ['url' => ''])
View Invoice
@endcomponent
Thanks,
{{ config('app.name') }}
@endcomponent