How's it going.Let me read of your question. Give me a minute.
Is the MAPI feature disabled on the exchange server and the users mailbox? Is this happening with all mailboxes
Open Exchange Management console and right click on their mailbox features
Powershell should be soothing like
Set-CASMailbox -Id $username -MAPI $false
MAPI was never a thing in 2003 this is why it would of been no issue before
Could I have a look in your exchange server?
The secure remote assistance is 49.95
When setting up the profile on the client. Can you use the exchange servers IP and not DNS name,
Please tell me If this works.
Can of give the user you are trying it on full access to the mailbox first.
I also need the RPC event log ino please
You can right click on the user in emc and manage full access persmisions.
Is SELF listed?
Exchange Management Console.
I will be honest you do not seem very clued up and remote connection would be the best.
what i can suggest are some trouble shooting methods to try to narrow down the problem
i would try
a. creating a new user and a new mailbox on the 2016 server
b. load a new version of outlook on a test computer and see if you can log into the user and then the new exchange server with that.
If that won't work than there is a problem with the exchange setup itself or the mapping to it.
if that will work than it probably has to do with something in the domain server equating the old exchange server with the user name or some other confusion where it is not sure which server to use because the same user has the same mailbox on both.
so just to be clear you created a new user id for the network that did not have a mailbox on the old server
you gave that user a mailbox on the new server
using a clean pc you logged in as that user and could not connect to the mailbox on the new exchange server
is that correct?
there is something wrong with either the network or the server.
does it have the same name as the old server ? that would screw it up.
the next thing that i might try just to be sure is to put the new server and a pc on their own network with nothing else on it and see if it can connect that way. You would probably have to do it by ip address or using a host file but if that does not work you have pretty much eliminated the network and it is something on the server itself.
Just for fun you might want to load a copy of oultlook 2016 and see if that gives you problems too. it should not make a difference but outlook and exchange are funny that way.
what domain is the new exchange server on ?