A matching connector cannot be found to route the external recipient

When I wanted to send an e-mail from my exchange mailbox to an external e-mail address, the message wasn't send.
I tracked the message in the Queue Viewer and it couldn't be sent because of this: "A matching connector cannot be found to route the external recipient".

To be able to send messages to external domains you have to create a send connector for domain "*". You can do this in the Organization Hub Transport Configuration:

530 5.7.1 Client was not authenticated

I got this error after sending an e-mail from an external domain over the internet to the exchange server, the message bounced with "530 5.7.1 Client was not authenticated" as error.
This is caused by the fact that I did not install an Edge Transport Server and did not specificly allow anonymous connections on the default receive connector.

By default Exchange 2007 servers not running the Edge Transport role will only accept inbound smtp connections from Exchange Users (clients), Exchange Servers (other Exchange 2007 servers) and Exchange Legacy Servers (legacy Exchange 2003 & below servers). To allow annonymous smtp connections for your server, run the following management shell command:

Set-ReceiveConnector -Identity "Default EXCHANGE" -PermissionGroups "AnonymousUsers"