Using AE 17.1.2 and Media Encoder 14.3.1
Is just impossible to export through media encoder and is sincerely quite frustrating because it gets me stuck and I can't deliver my project to my client.
Try this, launch Media Encoder and go to File > Add After Effects Composition and find the .aep-file with the comp/s you want to export.
I tried this and it's not working.
Any other solutions? or should we wait until another update?
That should work without issues so you have a problem with your computer or your project. My recommendation is to fix that, but until you do that you can use the Render Queue in Ae to export the material to let´s say Apple ProRes and then use those files in AME if you need to transcode them to H.264.
To fix, i would start with use the Creative Cloud Cleaner Tool to solve installation issues to wipe out the current installation of the Adobe apps and then re-installing them.
I fixed it and it worked