What exact number of Ae? and AME?
It says 2015.3 on both in Creative Cloud, but I have updated them so it says 2015.4 in the launch screen. So I presume it should be 2015.4 on both.
it's not specific enough. In each software click help- about. Ae should be 13.8.1 and AME 10.4.0
- how about trying the new and much better way of sending to AME, the "Add to Adobe AME" in the render queue?
- also try dragging your comp from Ae to AME ?
- also in AME file->add after effects composition?
all of these should work but maybe this could lead us to what exactly is happening.
- do you have a firewall or antivirus?
- try resetting your AME Preferences. hold shift and launch it. there will be no message for it (yeah it's weird)
- reset your AE preferences: hold Ctrl/Cmd+Alt+Shift and launch Ae. there will be a message for resetting preferences. click o.k
- see this thread also: some users found a solution, some didn't: Re: after effects cc 2015 won't export to Media encoder
- contact support: Contact Customer Care