The Email Delivery Logs say - retry timeout exceeded
If you see a delivery log that says - retry timeout exceeded
It means that message was not delivered.
Their ISP gave us a temporary error when we tried to delivered
We tried again in 20 minutes, 40 minutes, 60 minutes etc. However, the temporary error happened each time.
After 3 days of continuous trying, we gave up and that’s when you see the retry timeout exceeded error.
Copy and paste those logs and ask your subscriber to work with their ISP to correct the problem on their end.
Send them to http://www.mail-list.com/whitelist
where we will list our IP addresses and give them instructions on how to whitelist our machines to prevent this problem in the future.