Errors - No OPDS entries found

[vinser]

OPDS server response feeds causes "No OPDS entries found" errors.
Sample and simple server response:

<?xml version="1.0" encoding="UTF-8"?>
<feed xmlns="http://www.w3.org/2005/Atom" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:opensearch="http://a9.com/-/spec/opensearch/1.1/" xmlns:opds="http://opds-spec.org/2010/catalog">
  <title>John Marrs</title>
  <id>/opds/authors/id=147/anthology=alphabet/page=1</id>
  <updated>2024-03-23T12:19:39+05:00</updated>
  <link type="application/opensearchdescription+xml" title="Search on catalog" href="/opds/opensearch" rel="search"></link>
  <link type="application/atom+xml;profile=opds-catalog;kind=navigation" href="/opds" rel="start"></link>
  <entry>
    <title>The One</title>
    <id>/opds/books/id=224</id>
    <link type="application/fb2" href="/opds/books?id=224" rel="http://opds-spec.org/acquisition/open-access"></link>
    <link type="image/jpeg" href="/opds/covers?cover=224" rel="http://opds-spec.org/image"></link>
    <link type="image/jpeg" href="/opds/covers?thumbnail=224" rel="http://opds-spec.org/image/thumbnail"></link>
    <updated>2024-03-23T12:19:39+05:00</updated>
    <author>
      <name>John Marrs</name>
    </author>
    <content type="html"> A simple DNA test is all it takes. ... A word-of-mouth hit in the United Kingdom, The One is a fascinating novel that shows how even the simplest discoveries can have complicated consequences.</content>
  </entry>
</feed>

Response was was successfully tested with OPDS Validator
PocketBook, FBReader, Libera book reader apps has no problems with such responses.
At desktop Linux Foliate reader and Windows Thorium Reader process such responses too.

Please, help me with this error to fix my OPDS server and make it compatible with CoolReader app.