Question

After enabling campaign budget optimization, Facebook turned off several ad sets automatically. Is this expected behavior?

Answer 1

Yes, that behavior is expected when you enable Campaign Budget Optimization (CBO) in Facebook Ads.

Here’s why it happens:

When using CBO, Facebook automatically allocates your campaign’s budget across ad sets based on performance. If some ad sets are underperforming or not exiting the learning phase efficiently, Facebook may:

• Limit delivery to them significantly

• Or even turn them off entirely to maximize budget efficiency

This is part of the platform’s optimization logic. Instead of spreading budget evenly, CBO prioritizes ad sets that are driving the most results for the least cost.

What to Do About It

1. Review Ad Set Performance Metrics:

   • If an ad set has a high cost per result, low CTR, or poor conversion rate, Facebook may shut it down under CBO rules.

2. Use Ad Set Spend Limits (Optional):

   • You can apply minimum or maximum spend limits per ad set to ensure each gets enough budget for testing—but this can reduce CBO efficiency.

3. Test Ad Sets in Separate Campaigns:

   • If you want each ad set to get fair delivery, run them in individual campaigns without CBO to isolate performance.