Redemption "Error: Microsoft Exchange is not available" after moving mailboxes to Exchange 2016

Question

I'm facing troubles migrating some mailboxes from Exchange 2010 to Exchange 2016 because they are still used by an old application as part of some B2B flows. The application uses an old version of the Redemption.dll library (5.0.0.2174) to access mailboxes, get attachments and move the incoming e-mails to a subfolder “ELABORATED”. Everything is working on a Windows Server 2008 R2 server. Please don’t comment…

If we move mailboxes to Exchange 2016, we begin to see this error:

Error: Microsoft Exchange is not available. Either there are network problems or the Exchange server is down for maintenance. Component: Microsoft Exchange Information Store ulLowLevelError: 2147746069 ulContext: 1318 at Redemption.IRDOSession.GetSharedMailbox(Object NameOrAddressOrObject) at EmailActivatorLib.MapiExchangeProxy.GetInbox(MapiDelegate mailbox)

I’m not a software developer, but I have to understand if there is a way to move forward with migration possibly without changes on software side.

First of all, I would like to understand better how this library works.

1. Does Redemption library need an Outlook client installed on the same server to work?
2. Does Redemption library work only with MAPI protocol? Can we access mailboxes by IMAP instead?
3. If we were to figure out where the library file is, could a version update be enough? Is it necessary to register DLL again?
4. Which is the first version that is compatible with Exchange 2016? Or what version do you suggest?

Thanks in advance for your help. I’m fully available for further details.

Answer 1

I am not the author of Redemption library, but I'll try to answer all these questions posted (Dmitry may correct me if I am wrong):

Does Redemption library need an Outlook client installed on the same server to work?

Nope. The Redemption library is a wrapper around Extended MAPI, so it can be used with the standalone version of MAPI (but there may not be any profiles configured).

Does Redemption library work only with MAPI protocol? Can we access mailboxes by IMAP instead?

It should use protocols configured in your mail profile. This is a client-side library designed for dealing first-of-all with a local MAPI subsystem.

If we were to figure out where the library file is, could a version update be enough? Is it necessary to register DLL again?

Nope, that is not required if you don't import the type library. You may consider using the reg-free COM technology.

Also, similar to registry-free COM, you can explicitly load Redemption library and create instances of its creatable objects without registering the dll in the registry or even using an application manifest. On the low level, all in-proc COM libraries (dlls) export DllGetClassObject function that the COM system uses after looking up the dll location through the class name/CLSID in the registry. Since you know the Redemption dll location, there is no reason to create any registry entries for the COM system. See RedemptionLoader class for more information.

Which is the first version that is compatible with Exchange 2016? Or what version do you suggest?

Redemption is a wrapper around Extended MAPI (client-side), not server. The client-targeted wrappers don't depend on the server versions. So, instead of looking the first version compatible with Exchange 2016, I'd suggest checking the list of fixes and features that can be related to your case, see Redemption history.