This issue is due to the space between
<Link> tag and
So change your code like,
<div> <Link href="https://stackoverflow.com/"><a> Home </a></Link> <Link href="http://stackoverflow.com/about"><a> About </a></Link> </div>
Reason for the change:
<Link>can have only one child node and here the space between the
atag are considered as a child nodes.
-> So there are two child nodes (One is space and another is
<a>tag) which is invalid and hence such error occurs.