JAX-RPC has been deprecated and eventually removed from Java EE. As a consequence it's not available anymore in EAP 7 / WildFly 10. You need to upgrade your application to use more recent technologies (JAX-WS).
While this is the correct alternative, in case if there are dependencies on third party applications that use API dependent on JAX RPC, then you can exclude the module
<module name="javax.xml.rpc.api" />
This will allow you to supply your own JAXRPC API jar and the JAXRPC provider jar in your application classpath (part of the WAR or the JAR)
This fixed the issue for us.