When trying to run or test a web service integration, the integration faults with the following error:
This error means just what it says, that the port is already in use. Each web service integration will generate its own URL for use to keep it separate from other integrations. This means that the integration is running elsewhere.
Check both the Integration Builder and the Administration Console. Stop integrations in one application to run it in the other. So if you're running tests in the Integration Builder, stop the live integration in the Administration Console then you'll be able to test the integration just fine in Builder.
If this doesn't work and you still receive the error, follow the steps suggested in the message to allow the user to have permissions to use the port.