Warning: Illegal string offset ‘url’ in

I have leadership team custom fields of photo, name, title, and link (links to bio page). When I do not provide the url, this message (Warning: Illegal string offset ‘url’ in /var/www/html/wp-content/themes/xxxx/blocks/xxxx.php on line 16) is what appears above the leadership blocks. The goal is that when a url link is not provided the “View Button” will not appear Any suggestions?

<?php

$name = get_field('name');

$title = get_field('title');

$photo = get_field('photo');

$biolink = get_field('link');

(line16)echo'<a href="'.$biolink['url'].'" class=“leader”>;

if !empty( $photo ) )

echo w_get_attachment_image( $photo[ID'], 'thumbnail', null, array( 'class’ => 'leader--avatar’));

echo ‘<div class="leader--body">';

echo '<div class="leader--titles">';

if !empty( $name ) )

echo '<h4>' . esc_html( $name ) . '</h4>';

if !empty( $title) )

echo ‘<h6 class="alt”>’ . esc_htmi( $title ) . '</h6>';

echo '</div>';

if !empty( $biolink) )

echo ‘<div class="'leader--biolink">VIEW BIO</div>':

echo ‘</div>;

echo ‘</a>’;