TaxonomyList throwing error during template rendering

I've installed the TaxonomyList plugin and copied the
taxonomylist.html.twig file into my theme's partials/taxonomylist.html.twig.

The taxomony on blog posts is defined as:

taxonomy:
    category:
        - Health
    author:
        - 'Elaine Rush'

The problem is that when I run the site in the browser, the error

An exception has been thrown during the rendering of a template ("Illegal offset type in isset or empty").

is thrown.

It singles out the line {% for tax,value in taxlist[taxonomy] %} as being the problem.

Am I doing something wrong?

Have you defined your taxonomy properly in site.yaml ? Taxonomy docs