Probably, you have created a Rest-call that triggers a call that is different from your expectation. Mendix has provided a way for you to check the Rest-call requests that come from your microflow: in StudioPro run your app locally, open your Console, click Advanced, click set log levels. Set the log level ‘Rest consumed’ to Trace. Now using your application, generate a rest call, and check your console’s log. You will find your call in detail and will probably see that you have a different target host compared to what you expected.
Go back to your microflow, open the rest call activity, and correct the location.
Here is how a REST call I created looks like. Does yours look similar?
Another test, if you put your equivalent of my Location in the browsers URL, do you get to see something like this:
Hope this helps!