getUrl got "internal exception" return.

getUrl got "internal exception" return.

The code of the custom function is as the following.

-------------------------------------------------------------------------

header = map();
header.put("AuthenticationToken", "xxxxx-dsfads-ewrw-ddd-yyyyyyyyy");
response=getUrl(url,header,false);

info response;

return 0;
---------------------------------------------------------------------------
I have got the following response

{"responseText":"internal exception","responseCode":"-1"}

But the same call returns the correct JSON data via postman.

What could be the reason? 

Anyone had the same problem? What was the solution?