Having a problem with this, was working fine for over a year but now getting this error fairly regularly.

Office network connected to SBS2011 domain
Using hosted exchange with Outlook on the systems
Occasionally Outlook will not send/receive messages - error (0x80040115)
I am certain it is to do with the DNS, I think the mailserver IP is being cached and when the mailserver IP changes Outlook is connecting to the old IP
ipconfig /flushdns on the clients doesn't usually remedy but rebooting the Draytek router does

So my question is do you think I am right, and if so is it the DC that is caching the DNS? Does rebooting the router cause the DC to update?

I need to look at my client ipconfig /all to confirm what DNS servers they are using (pretty sure it will be the DC IP) but if I flush them and they still pick up the wrong IP I assume it must be the DC, can't see the router caching and I don't have the same problems here with same router and same hosted exchange provider (with no DC).

Would I exclude the mailserver domain from caching or set it to update on a more frequent basis?

Cheers