Safari 10.1: XMLHttpRequest with query parameters cannot load due to access control checks

Question

When trying a CORS request on Safari 10.1, on an URL which includes query parameters (e.g. https://example.com/api?v=1), Safari says

Answer 1

If anyone comes across this error, it just occurred in the application I was building. In my case, it turned out to be a trailing / in the uri, which caused a 301 response, which was for some reason interpreted by Safari as a 500 response.