There is a 2-step artwork approval process when you upload one into the platform. Firstly, my team has to review it to make sure it abides by our ad policy. Then, once we’ve confirmed this, the artwork is sent to the media owner(s) that are relevant to that artwork.
Step 1 typically happens in less than 24 hours, however Step 2 varies a lot between media owners/publishers. In general though, try and allow a minimum of 48 hours for artwork approval (both steps), but expect this to sometimes take up to 7 business days.
If an artwork is taking even longer to get approved, please reach out and let the team know.