Question about Ubiquiti UniFi Dream Machine Pro

Which SPF is required if I want to connect the WAN port to the 2.5GB Lan port of a Sunrise router? I already have a module, but it does not work. I can't get an IP address on the WAN port. I have adjusted the settings several times, but unfortunately it does not work. As soon as I reconnect the Sunrise router to port 9, it works. So I assume that I am using the wrong SPF+ module.