404 when accessing Solr core after installing Sitecore Experience Commerce 9.0.2

3912 16:01:58 ERROR Unable to connect to [https://localhost:8983/solr], Core: [sitecore_sxa_web_index]
Exception: SolrNet.Exceptions.SolrConnectionException
Message: <html>
<head>
<meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
<title>Error 404 Not Found</title>
</head>
<body><h2>HTTP ERROR 404</h2>
<p>Problem accessing /solr/sitecore_sxa_web_index/schema. Reason:
<pre>    Not Found</pre></p>
</body>
</html>

Source: SolrNet
   at SolrNet.Impl.SolrConnection.Get(String relativeUrl, IEnumerable`1 parameters)
   at Sitecore.ContentSearch.SolrNetExtension.Impl.SolrBasicServerEx`1.GetSchema(String collection)
   at Sitecore.ContentSearch.SolrProvider.SolrSearchIndex.InitializeSchema()
   at Sitecore.ContentSearch.SolrProvider.SolrSearchIndex.InitializeSolr()

Nested Exception

Exception: System.Net.WebException
Message: The remote server returned an error: (404) Not Found.
Source: System
   at System.Net.HttpWebRequest.GetResponse()
   at HttpWebAdapters.Adapters.HttpWebRequestAdapter.GetResponse()
   at SolrNet.Impl.SolrConnection.GetResponse(IHttpWebRequest request)
   at SolrNet.Impl.SolrConnection.Get(String relativeUrl, IEnumerable`1 parameters)

While the default Sitecore 9 installation script sets the core name to a custom value, the XC file Sitecore.XA.Foundation.Search.Solr.config is still $(id) and queries are made to a core that does not exist. Updating the value to match your actual core name resolves this issue.