After submitting your campaign for approval, the approval team will review your campaign within 24 hours, if all's valid will be happy to approve your campaign.
If the approval team has decided to deny your campaign or creative, you will receive a denial notification to your email that will specify the reason for the denial.
Our approval team is highly sensitive to campaign content since our traffic is direct in-app traffic and we are obligated to keep our traffic aligned with Google and iTunes restrictions.
See stores policies:
Apple App Store: https://developer.apple.com/app-store/review/guidelines/#advertising
Reasons For Denial
A campaign may be denied for the following reasons:
Misleading creatives and landing pages that are mimicking a UI or a system alert will be denied.
A campaign will be denied if it contains inappropriate images or texts.
If your tracking URL doesn't lead to a valid landing page, your campaign will be denied.
Creatives do not match the landing page your tracking URL leads to.