In Exchange 2012 by default the maximum size message you can receive is 36mb, this limit is determined by a receive connector , specifically the default front end server. To increase this we can do it two ways, either via powershell of via the gui – Exchange Admin Center.Obviously this value can also be decreased.
Increase Maximum Receive Message Size With Powershell Exchange 2013
To do this launch the Exchange 2013 Exchange Management Shell and enter the command below.
Firs get the name of you connector with
Set-ReceiveConnector -Identity Defaultconnector -MaxMessageSize 54096
Where “Default connector” is the name of your default frontendTransport Connector and MaxMessageSize is set to 54meg here.
Now restart the Microsoft Exchange transport Service to complete the task.
Increase Maximum Receive Message Size With Exchange Admin Center
We first need to launch the EAC and select Mail Flow
Once done we then select Receive Connectors and select the Default Frontend YOURSEVERNAME connector.Once done, select the pencil to edit.As you can see below, in the general tab you can edit the maximum receive message send size to what you would like to use. Do so and click save..
Again restart the Microsoft Exchange Transport service to make these changes take effect.