Export creates MP4 but does not upload to YT...?

Ok...I can't seem to figure this one out in my Premiere Pro CC.

Sometimes, when I do an export to YouTube, the rendering process looks like it does just fine but then Premiere exits the Export dialog and that's it.  I'm back to the main editor, in my project, with no message to tell me if it finished or not.  Actually...that happens all the time, but I'm often here when it finishes, so I know it's done.

The .MP4 file is on my drive and it's fine.  More oft than not, the file was uploaded to YouTube, so I just wait for it to finish being checked out by YT's software, then edit the entry in Creator Studio.  Sometimes, though, the upload does not occur.  In one case, I found that the app had updated and my YT creds were gone.  Just now it happened again but the file did not upload and Premiere Pro provided no error message or anything. 

How do I get the results of the render/upload?  I know for a fact my credentials were there and that YouTube was ticked in the publish options; I even typed in the whole description and set it to public which you can't do without ticking the box.  It definitely did not upload, though - the video was fully rendered and I'm uploading it manually, but I'd like to know what went wrong.

I'm on a Mac, so I went into the Documents/Adobe folder looking for a log file - there are none there in any of the sub-folders. 

Suggestions...?