My exchange was running before without problems untill users on one  DAG server started getting Outlook Disconnected errors. I moved the databases to another DAG and everyting is ok. We have 3 CAS and 3 MBX, I am experiencing this problem on one DAG. When I move the user database to another DAG and do the same test, no problems.This is Exchange 2013 on Windows 2012R2 (Vmware). Checked internet but talks of CAS servers. Where do I start to troubleshoot

I ran testexchange connectivity on a mailbox on the problem server and got the error message

Attempting to ping the MAPI Mail Store endpoint with identity: 67f551f8-05b5-45db-b2d9-39b537eefdbd@sisecam.com:6001.   The attempt to ping the endpoint failed.   Additional Details   An RPC error was thrown by the RPC Runtime process. Error 1630 1630   Elapsed Time: 5293 ms.

Hi

Can you please explain your DAG setup ?

Can you run Get-MailboxDatabasecopystatus and see the results

Each DAG has 4 active copies, 4 passive copies and 4 lag copies. Since I started getting problems on databases on one DAG I mounted them to the other two DAGs, so the   problem DAG is hosting passive copies only. I have created a test database on this DAG, created a test user account for troubleshooting and testing mounted.

CAS servers and Mailbox servers are on different servers

We had some issues with our Exchange so for best practices someone set the following settings on the DAG servers, we  set them to the original values everything is ok.

Minimum Connection Timeout. Configure the RPC timeout on Exchange servers to make sure that components which use RPC will trigger a keep alive signal within the time frame you specify here. This will help keep network devices in front of Exchange from closing sessions prematurely:
HKLM\Software\Policies\Microsoft\Windows NT\RPC\MinimumConnectionTimeout
DWORD  0x00000078 (120 decimal)
 
Set Keep alive timeout. Determines how often TCP sends keep-alive transmissions. TCP sends keep-alive transmissions to verify that an idle connection is still active. Many network devices such as load balancers and firewalls use an aggressive 5 minute idle session time out. This will help keep those devices from closing a session prematurely:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveTime
DWORD value = 900000

We had some issues with our Exchange so for best practices someone set the following settings on the DAG servers, we  set them to the original values everything is ok.

Minimum Connection Timeout. Configure the RPC timeout on Exchange servers to make sure that components which use RPC will trigger a keep alive signal within the time frame you specify here. This will help keep network devices in front of Exchange from closing sessions prematurely:
HKLM\Software\Policies\Microsoft\Windows NT\RPC\MinimumConnectionTimeout
DWORD  0x00000078 (120 decimal)
 
Set Keep alive timeout. Determines how often TCP sends keep-alive transmissions. TCP sends keep-alive transmissions to verify that an idle connection is still active. Many network devices such as load balancers and firewalls use an aggressive 5 minute idle session time out. This will help keep those devices from closing a session prematurely:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\KeepAliveTime
DWORD value = 900000

• Proposed as answer by Winnie LiangMicrosoft contingent staff, Moderator 23 hours 33 minutes ago