The URL from the endpoint has to been fix (as far i test it). May be there is a possibility to work with variables but the logfiles arent detailed enough to find the real reasons.
My Workaround (that worked for me) use following circumstances:
- Generate Datatable
- Generate variables
- Import the csv file into the datatable
- Generate a for each Loop
- HTTP Request
In the HTTP Request you can use the variables in Parameters and URL Segments.
An Example from you JSON Example Video:
api.openweathermap.org must be fix
/data /2.5 / weather? could be URL Segments that can be generated through variables
q=London,UK could be a variable trough the Parameters Settings.