I am using webservicequery function to get list of all Cities (

The result you are seeing is expected, there is nothing wrong with your webservicequery in this case. I tested all the other operations for that port and they work fine. However GetXmlData does not work because it returns an XML node, which in this case likely contains unsupported types. I see the following error in my server.log when performing this operation:

The XSD could not be imported because it contains the unsupported construct: mixed content for complex types. No types have been imported.

This matches up with one of the expected errors in our documentation on importing XSDs:
forum.appian.com/.../Defining_a_Custom_Data_Type
Under the section "Possible Errors When Importing"

The result you are seeing is expected, there is nothing wrong with your webservicequery in this case. I tested all the other operations for that port and they work fine. However GetXmlData does not work because it returns an XML node, which in this case likely contains unsupported types. I see the following error in my server.log when performing this operation:

The XSD could not be imported because it contains the unsupported construct: mixed content for complex types. No types have been imported.

This matches up with one of the expected errors in our documentation on importing XSDs:
forum.appian.com/.../Defining_a_Custom_Data_Type
Under the section "Possible Errors When Importing"