Yes, the file definitely exists.
And here’s the test result online (I test it with window 7 64-Bit, 3 browser : IE, Firefox, and chrome):
1. IE - 5 times reload = 5x error type TEXT (.json) with different file
2 Firefox - 5 times reload = 1x error a lot of file type and 4x success
3 Chrome - 5 times reload = no error always success
But If I test it localhost, almost always successfull in 3 browser. Except IE and FF from 10 times try localhost maybe only 1x error.
I hope this information helpfull.
Thanks