After upgrading gateway to 11.x gateway logs shows the following error
com.l7tech.server.globalresources.SchemaResourceManager: Multiple (4) XML Schemas found with target namespace 'http://schemas.xmlsoap.org/soap/envelope/', unable to register for hardware.
GW 11.x
To resolve thus check in policy manager your global resources for duplicates
Go to tasks / global settings / global resources
Make sure there are no duplicates .