You have drawing errors, as the ones pointed out by @daniellei4510, but you have also compression (!) artefacts, that need to be addressed before submission.
The white boreder per se would not be a problem, but the lines are aliased, that's also a defect.
The line is also not consistently the same size. You also see on the second asset easily the drawing errors, besides the fact, that there is not a consistent black.
ABAMBO | Hard- and Software Engineer | Photographer