CRM 2015 On Premise Organisation / Discovery Service URLs

Hi 

In our CRM 2015 deployment, at the beginning it worked fine after having a few changes in the infrastructure (unfortunately no idea what they did) we are experiencing the following issues in the deployment

In the System Customization -> Developer Resources the web services URLs are displayed in the following way

Organisation Service

http://ServerName(Not FQDN)/Org/XRMServices/2011/Organization.svc 

Discovery Service

http://ServerName(Not FQDN)/Org/XRMServices/2011/Organization.svc

Is there any configuration which will fix the above service urls (with FQDN)?

And also we couldn't start the Sandbox Processing Service, following error message is logged in the event viewer 

The Sandbox SDK Listener failed to start.
Source: w3wp.exe (4628)

Any help is much appreciated 

Thanks in Advance

Tenison