ovirt-engine-extensions-tool fails with message:"Connection timed out"

Issue

The login via extensions-tool fails with

java.net.ConnectException: Connection timed out (Connection timed out)'

Snippet from the log file

2017-05-09 10:37:38 FINE    Creating LDAPConnectionPool
2017-05-09 10:38:41 FINE    Sequence ad-open-pools create gc pool failed due to exception: An error occurred while attempting to connect to server 1.2.3.4:3268:  java.io.IOException: LDAPException(resultCode=91 (connect error), errorMessage='An error occurred while attempting to establish a connection to server / 1.2.3.4:3268:  java.net.ConnectException: Connection timed out (Connection timed out)')
2017-05-09 10:37:38 FINE    ServerSet: SingleServerSet(server= 1.2.3.4:389)
2017-05-09 10:37:38 FINE    Creating BindRequest
2017-05-09 10:37:38 FINE    createBindRequest Entry type='simple', user=''
2017-05-09 10:37:38 FINE    createBindRequest Return SimpleBindRequest(dn='CN=test,CN=Users,DC=test,DC=test')
2017-05-09 10:37:38 FINE    BindRequest: SimpleBindRequest(dn='CN=test,CN=Users,DC=test,DC=test')
2017-05-09 10:37:38 FINE    Creating LDAPConnectionPool
2017-05-09 10:37:38 FINE    createConnectionPool Return: LDAPConnectionPool(serverSet=SingleServerSet(server= 1.2.3.4.3:389), maxConnections=20)
2017-05-09 10:37:38 INFO    [ovirt-engine-extension-aaa-ldap.authz::test-authz] LDAP pool 'authz' information: vendor='null' version='null'