Impossible to access an attribute ("name") on a null variable.
<div class="block-contact-person-text__title">
Ihr Ansprechpartner
</div>
<div class="block-contact-person-text__name">
{{ contact_person.name }}
</div>
<div class="block-contact-person-text__position">
{{ contact_person.position }} am Standort {{ contact_person.location }}
</div>