I have an Exchange 2010 SP1 server (SBS 2011).
We try to send to some wanadoo addresses of our customers and we get the following message back: The server has tried to deliver this message, without success, and has stopped trying. Please try sending this message again. If the problem continues, contact your helpdesk.
I have tried to send it from gmail and it works. I get an answer the message received well.
I don't understand why. Can someone help me?
One thing: Last week I removed the forwarders of my DNS (I used the forwarders from google and opendns). The reason for removing was problems on my network. This problems are solved after removing the forwarders.
Maybe this is a part of the problem? Maybe I need forwarders?
When I have to use forwarders, which forwarders are the best to use? Maybe the forwarders of my ISP?