LDAP Failed to initialize AuthService

Hello.

In the virtual machine (VMware ESXi 6) installed Debian 9.
Installed xwiki-tomcat8-pgsql.
Installed LDAP extension with the Extension Manager.

Add to /etc/xwiki/xwiki.cfg following properties

xwiki.authentication.authclass=org.xwiki.contrib.ldap.XWikiLDAPAuthServiceImpl
xwiki.authentication.ldap=1
xwiki.authentication.ldap.trylocal=1

Enable LDAP debugging in /etc/xwiki/logback.xml

logger name=“org.xwiki.contrib.ldap” level=“trace”

Restart tomcat8

In /var/log/tomcat8/catalina.out found

2019-05-29 14:06:28,772 [http://192.168.0.93:8080/xwiki/bin/loginsubmit/XWiki/XWikiLogin]
WARN c.x.x.XWiki - Failed to initialize AuthService org.xwiki.contrib.ldap.XWikiLDAPAuthServiceImpl using Reflection, trying default implementations using ‘new’.
java.lang.ClassNotFoundException: org.xwiki.contrib.ldap.XWikiLDAPAuthServiceImpl
at org.xwiki.classloader.URIClassLoader$1.run(URIClassLoader.java:193)

LDAP even not start.
Any suggestions how to fix it?

This suggest that the extension was not loaded. Do you have any warning/error at startup related to extensions ?