Cannot get DDNS working on my Dual WAN failover setup.

[l3rady]

I'm running pfSense 2.5.2-RELEASE.

I have one pfSense router that I cannot get DDNS to work for the life of me. I've tried both Cloudflare and route53 DDNS clients and they both fail with an error like:

Dec 22 16:31:39	php-fpm	348	/services_dyndns.php: Curl error occurred: Could not resolve host: route53.amazonaws.com

Looking at the logs it works out the correct public IP but for whatever reason when it goes to the client API to send the IP the curl request fails. I have similar setups elsewhere and they all work fine with the same configuration.

When I click save on the DDNS settings it takes over a minute to save as it attempts to update the DDNS. It seems that it does try to make the connection to the API but then times out after 60s.

If I run curl https://route53.amazonaws.com from the command line it returns expected data. Pings, traceroutes, and general web browsing all function correctly.

My WAN setup is as follows:

I have a gateway group set up as failover:

And my default gateway set as the failover:

My DDNS settings monitor the failover group:

My DNS settings are as follows:

Firewall rules are set as a default install bar adding a LAN anywhere rule and allowing the two WAN interfaces to be pinged for outside monitoring. Outbound NAT rules are auto.

Everything is configured as bog-standard but for the life of me cannot work out why DDNS won't work.

What can I do to further diagnose the issue to find where the problem might lie?