Google Rich Results Test - Item does not support reviews

I was trying out a bunch of things on Google's Rich Results Test, and ran into this issue.

<html>
  <head>
  <title>Test SEO</title>
    <script type="application/ld+json">
    {
       "@context":"https://schema.org",
       "@type":"Service",
       "name":"ABC",
       "aggregateRating":{
          "@type":"AggregateRating",
          "ratingValue":5,
          "reviewCount":2
       },
       "review":[
          {
             "@type":"Review",
            "name": "ABC",
             "author": {
               "@type": "Person",
               "name": "David A"
             },
             "reviewBody":"Awesome",
             "reviewRating":{
                "@type":"Rating",
                "ratingValue":5
             }
          },
          {
             "@type":"Review",
            "name": "ABC",
             "author": {
               "@type": "Person",
               "name": "David B"
             },
             "reviewBody":"Great",
             "reviewRating":{
                "@type":"Rating",
                "ratingValue":5
             }
          }
       ]
    }
   </script>
   </head>
   <body>
   </body>
</html>

When I ran the test, it returned 3 errors, 2 of them saying Item does not support reviews, and 1 of them saying Invalid object type for field 'itemReviewed'.

For the first error, I'm not sure why I'm getting the error as I provided all the required fields for a review (https://developers.google.com/search/docs/advanced/structured-data/review-snippet#review-properties).

As for the second error, again I think I provided all the needed fields according to https://developers.google.com/search/docs/advanced/structured-data/review-snippet#aggregated-rating-type-definition, but still getting back that error.

I didn't provide itemReviewed to either objects, since the document indicated if it's nested, it can be omitted.