This is an old post, but it doesnt work for me, just throw it here:
Regarding the OAuth issue, one of the engineering managers discovered something about the data copying that may cause an issue during validation. What he said was that if he text-select the filename by dragging the mouse, it is possible to pick up the "newline" character at the end of the filename. Essentially selecting the filename plus the empty line right after the filename. This may be an issue for some of you - but the problem is still being looked into for a more reliable solution.