Conversions not showing in Marketing API for Facebook (Field is empty or disallowed by the access token)

Response example not showing conversions:

I'm trying to retrieve some ads insights so I can use them in my custom dashboard, everything is good but anything is related to conversions(results) is not returning in response. I gave all permissions to the access token and still no results.

What's the problem and how can I get this conversions/leads/results?

this is the required permissions for reading ads: read_insights, ads_management, ads_read, business_management, leads_retrieval. all of them included in the access token.