solr search not working and logging fatal errors

[INFO] [talledLocalContainer] [Fatal Error] :17:75: The reference to entity "_hn:ref" must end with the ';' delimiter.[INFO] [talledLocalContainer] [Fatal Error] :17:75: The reference to entity "_hn:ref" must end with the ';' delimiter.[INFO] [talledLocalContainer] Nov 11, 2019 10:46:09 AM org.apache.catalina.core.ApplicationDispatcher invoke[INFO] [talledLocalContainer] SEVERE: Servlet.service() for servlet [jsp] threw exception[INFO] [talledLocalContainer] org.xml.sax.SAXParseException; lineNumber: 17; columnNumber: 75; The reference to entity "_hn:ref" must end with the ';' delimiter.[INFO] [talledLocalContainer]  at com.sun.org.apache.xerces.internal.parsers.DOMParser.parse(DOMParser.java:257)[INFO] [talledLocalContainer] 11.11.2019 10:46:09 WARN  http-nio-8080-exec-5 [HstComponentInvokerImpl.logComponentException:255] Component exception caught on window right with component org.hippoecm.hst.demo.components.SolrRight: org.apache.jasper.JasperException: javax.servlet.ServletException: javax.servlet.jsp.JspException: org.xml.sax.SAXParseException; lineNumber: 17; columnNumber: 75; The reference to entity "_hn:ref" must end with the ';' delimiter. at org.apache.jasper.servlet.JspServletWrapper.service(JspServletWrapper.java:499)[INFO] [talledLocalContainer]  at com.sun.org.apache.xerces.internal.jaxp.DocumentBuilderImpl.parse(DocumentBuilderImpl.java:339)[INFO] [talledLocalContainer]  at org.hippoecm.hst.tag.HeadContributionTag.doEndTag(HeadContributionTag.java:106)[INFO] [talledLocalContainer]  at org.apache.jsp.WEB_002dINF.jsp.components.main.solrright_jsp._jspx_meth_hst_005fheadContribution_005f3(solrright_jsp.java:1006)[INFO] [talledLocalContainer]  at org.apache.jsp.WEB_002dINF.jsp.components.main.solrright_jsp._jspService(solrright_jsp.java:287)[INFO] [talledLocalContainer]  at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:70)