At some occasions user get an error message while logging in and Confluence drops the following message in its log:

Caused by: javax.naming.CommunicationException: xldaps.hamburg.rwedea.de:3269 [Root exception is java.net.BindException: Address already in use: connect]
at com.sun.jndi.ldap.Connection.<init>(Connection.java:197)
at com.sun.jndi.ldap.LdapClient.<init>(LdapClient.java:118)
at com.sun.jndi.ldap.LdapClientFactory.createPooledConnection(LdapClientFactory.java:46)
at com.sun.jndi.ldap.pool.Connections.getOrCreateConnection(Connections.java:185)
at com.sun.jndi.ldap.pool.Connections.get(Connections.java:126)
at com.sun.jndi.ldap.pool.Pool.getPooledConnection(Pool.java:129)
at com.sun.jndi.ldap.LdapPoolManager.getLdapClient(LdapPoolManager.java:310)
at com.sun.jndi.ldap.LdapClient.getInstance(LdapClient.java:1572)
at com.sun.jndi.ldap.LdapCtx.connect(LdapCtx.java:2652)
at com.sun.jndi.ldap.LdapCtx.<init>(LdapCtx.java:293)
at com.sun.jndi.ldap.LdapCtxFactory.getUsingURL(LdapCtxFactory.java:175)
at com.sun.jndi.ldap.LdapCtxFactory.getUsingURLs(LdapCtxFactory.java:193)
at com.sun.jndi.ldap.LdapCtxFactory.getLdapCtxInstance(LdapCtxFactory.java:136)
at com.sun.jndi.ldap.LdapCtxFactory.getInitialContext(LdapCtxFactory.java:66)
at javax.naming.spi.NamingManager.getInitialContext(NamingManager.java:667)
at javax.naming.InitialContext.getDefaultInitCtx(InitialContext.java:288)
at javax.naming.InitialContext.init(InitialContext.java:223)
at javax.naming.InitialContext.<init>(InitialContext.java:197)
at javax.naming.directory.InitialDirContext.<init>(InitialDirContext.java:82)
at com.atlassian.user.impl.ldap.repository.DefaultLdapContextFactory.getLDAPContext(DefaultLdapContextFactory.java:89)
... 229 more
Caused by: java.net.BindException: Address already in use: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:525)
at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:550)
at sun.reflect.GeneratedMethodAccessor128.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at com.sun.jndi.ldap.Connection.createSocket(Connection.java:297)
at com.sun.jndi.ldap.Connection.<init>(Connection.java:184)
... 248 more