Depends on what protocol you are using.
If its HTTP (and what isn't these days?), then there's been an "internal server error". Perhaps the webservice you are trying to use has a bug. Perhaps you are sending it bad data and its not catching it until it makes thinks mess up.
In any case HTTP 500 means that theres an error on the other end. Maybe you should have a second look at the API.

In reply to Re^3: File does not exist: 500 read failed by plobsing
in thread File does not exist: 500 read failed by CColin

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