We usually encounter below error when we deploy SOA Composite to server.
[12:17:36 PM] Error deploying archive sca_SampleBPEL_rev1.0.jar to partition "Default" on server LOCAL_SOA [http://localhost:8001]
[12:17:36 PM] HTTP error code returned 
[12:17:36 PM] Error message from server:
There was an error deploying the composite on LOCAL_SOA: Deployment Failed: Unable to register service.
[12:17:36 PM] Check server log for more details.
[12:17:36 PM] Error deploying archive sca_SampleBPEL _rev1.0.jar to partition "Default " on server LOCAL_SOA [http://localhost:8001]
[12:17:36 PM] #### Deployment incomplete. ####
[12:17:36 PM] Error deploying archive file:/C:/JDeveloper/mywork/TestApplication/SampleBPEL/deploy/sca_SampleBPEL _rev1.0.jar
We cannot identify what exactly causing this by seeing above error. But below are the main reasons for above error.
· WSDL or XSD is not deployed to MDS (Missing MDS deployment)
· Something is wrong with WSDL or XSD.
· XSD references in your WSDL is not right.
To see the exact cause you can check the SOA server Diagnostic log file. You can find that file at below location.
user_projects / domains / <your domain> / servers / <your soa server> / logs / <you soa server>-diagnostic.log.