Using multiple providers

Is it possible to use multiple providers to update different domains? I tried this config (simplified)

{
    dynamic_dns {
        provider cloudflare {$CLOUDFLARE_API_TOKEN}
        domains {
            main-domain.com
        }
    }

    dynamic_dns {
        provider duckdns {$DUCKDNS_TOKEN}
        domains {
            secondary-domain.com
        }
    }
}

but it seems like only the second dynamic_dns block (for DuckDNS) is functional; main-domain.com is not updated at all.