Error: test_ssl_fetch_new_certificate(SSLTest): OpenSSL::X509::RequestError: illegal zero content

Error: test_ssl_fetch_new_certificate(SSLTest): OpenSSL::X509::RequestError: illegal zero content
/usr/lib/ruby/3.1.0/openssl/x509.rb:387:in `to_der'
/usr/lib/ruby/3.1.0/openssl/x509.rb:387:in `=='
/etc/sympl/test.d/tc_ssl.rb:745:in `test_ssl_fetch_new_certificate'
     742:     assert_equal(set.bundle, [ca_cert])
     743:     assert_equal(set.key, key)
     744:     assert_equal(set.certificate, cert)
  => 745:     assert_equal(set.request, request)
     746:
     747:     assert_equal("0", @domain.ssl_next_set_name)
     748:     set.name = "0"