One of the problems with timeout is that something is wrong with the client link in OTOY-EC2-AMI.pdf.
If you copy/paste that link, you will need to manually retype all semicolons. You can see that something is wrong if you paste the link in Firefox address bar and then copy/paste it again. All semicolons will be replaced with %CD%BE except the ones you typed manually.
One other thing that can also create timeout problem is that if you are using automatic GUID, it can change while connecting and disconnecting with the client. Safest thing is to have an open RDP connection and copy or retype GUID from process list, just before connecting with the client.