Webservice call returns 301 (#CON11)

[30knees]

I'm trying to link an external service but the connection attempt gives this error:

This call to PrestaShop Web Services returned an unexpected HTTP status of:301 (#CON11)

I activated logs for the webservice but no logs are generated.

I've read https://docs.prestashop-project.org/1-6-documentation/english-documentation/developer-guide/developer-tutorials/using-the-prestashop-web-service/web-service-tutorial/chapter-2-discovery-testing-your-access-to-the-web-service-with-the-browser and tried accessing via http://mypasskey@example.com/api/. This is unsuccessful. I'm am only asked to enter the passkey again and again. The tutorial says:

Quote

If no permission has been set for the key, than the browser will keep asking you to enter the key indefinitely.

However, the key was associated with full permissions.

How can I figure out what the problem is? 

[30knees]

Solution: The domain in the external service and the tb parameter SET SHOP URL have to match precisely. The external service said to use domain.com but in SET SHOP URL I had www.domain.com. Changing the external service entry to www.domain.com fixed the issue.