Exchange 2016 relaying

Hi,

I have a FortiMail VM01 and its currently relay mail for my Lotus Mail servers.

I have built two new Exchange 2016 servers and on them I created a send connector that sends to the IP of the Fortimail device for domain *.mysmtpdomain.com

On the Fortimail device I went to Policy -> Access Control and added the IP addresses of my two Exchange servers in here.

I testing I can telnet from the two Exchange servers  to Fortimail on port 25.

But still Fortimail wont deliver mail externally from my Exchange servers, hours after sending my test mails I get the following bounce back - returned '550 4.4.7 QUEUE.Expired; message expired in unreachable destination queue. Reason: A matching connector cannot be found to route the external recipient'

Any advice ???