When set the message size limits for incoming and outgoing email & attachments size, Please take under consideration the other side message size limitation .
Change the defaults on the connectors by names, this example will set limit of 50mB for the receive connector & Send Connector :
Get-ReceiveConnector | fl name Set-ReceiveConnector “CONNECTOR NAME” -MaxMessageSize 50Mb
Get-SendConnector | fl name Set-SendConnector “CONNECTOR NAME” -MaxMessageSize 50Mb Get-TransportConfig | ft MaxSendSize, MaxReceiveSize Set-TransportConfig –MaxSendSize 50MB –MaxReceiveSize 50MB
You can also change those limits settings for each user, To get all the mailbox’s setting and set for individual mailbox limits :
Get-mailbox | ft Name, MaxSendSize, MaxReceiveSize
Set-Mailbox “test” –MaxSendSize 30MB –MaxReceiveSize 30MB
Additional information can be found here