I am having a strange issue with ASA 5520. It acts like a router between MPLS sites and a central site. Everything works good except for the Outlook -> Exchange traffic, users can see messages like: Outlook is trying to retrieve data from the Microsoft Exchange Server, and also that the network is too busy to send messages. When I plug the MPLS router directly to the core switch, it works great.
ip address 10.20.20.92 255.255.255.0
description MPLS Router
ip address 172.17.255.2 255.255.255.0
I have enabled communication between interfaces with the same security level, and there is no access-list on both interfaces...