Why is my Naver ad setup still failing after approval?

Following up on my previous post regarding initial Naver PPC campaigns, I've managed to resolve the basic setup errors. All my ads and keywords are now showing 'Approved' status within the Naver Ads console, which was a significant hurdle cleared.

Despite this 'Approved' status across the board – for campaigns, ad groups, keywords, and creatives – my campaigns are still registering zero impressions over the past 48 hours. This suggests a deeper technical issue beyond simple policy violations or initial setup errors, something that's silently preventing ad serving.

I suspect this might be related to a subtle targeting conflict, an obscure bid strategy misconfiguration, or an account-level setting that silently suppresses delivery even post-approval. I've meticulously re-checked geo-targeting, daily budgets, and general keyword relevance, and everything appears to be configured correctly. This persistent lack of impressions points to complex Naver delivery issues that aren't immediately obvious.

When querying the campaign status via the Naver Ads API (or checking the detailed console view), the status consistently shows:

{
  "campaignId": "CMP_12345",
  "campaignName": "Service_Launch_KR",
  "status": "ACTIVE",
  "adGroupStatus": "ACTIVE",
  "keywordStatus": "APPROVED",
  "adCreativeStatus": "APPROVED",
  "deliveryStatus": "NOT_DELIVERING_CONSISTENTLY",
  "lastImpressionTimestamp": null,
  "diagnosisNotes": "Potential bid competitiveness or targeting audience too narrow."
}

What are the advanced diagnostic steps or less obvious technical checks for Naver ad setup that could explain zero impressions even with fully approved campaigns and keywords? Are there specific Naver API calls or console views to identify these silent delivery blockers?