Trying to synchronize the application list results in a timeout and following log entry can be found:

2017-08-15 13:52:22.971 [http-nio-8080-exec-3] ERROR c.c.r.c.c.RestControllerAdvice - Connection timeout on call to http://10.130.97.21:8080/cdd-ra-plugin/api/application-source/applications with args [Ar 
gument{name='apiUrl', value='http://10.130.97.21:8080/cdd-ra-plugin/api/application-source/applications'}] 

com.ca.rp.exceptions.rest.PluginException: Connection timeout on call to http://10.130.97.21:8080/cdd-ra-plugin/api/application-source/applications 

timeout settings in settings.properties are set too small

Continuous Delivery Director 6.x

Locate the settings.properties file within the CDD home folder (default /root/.cdd in Linux, C:\.CDD in Windows). 

Check the existence of following lines:

cdd.plugins.client.http.connection.timeout=600000
cdd.rest_template.connect.timeout=600000
cdd.plugins.client.http.read.timeout=600000
cdd.rest_template.read.timeout=600000

If they exist, change them to:

cdd.plugins.client.http.connection.timeout=1800000
cdd.rest_template.connect.timeout=1800000
cdd.plugins.client.http.read.timeout=1800000
cdd.rest_template.read.timeout=1800000

If they do not exist, add those lines.

Afterwards restart Tomcat.