Original User: santiago1780
Shortly after posting the original post, my fate was exactly the same "The package upload failed.. make sure you're connected to the internet..."
However, I've never got that "not signed in to ArcGIS Online" error. Make sure you're entering your password (allthough you did connect at some point, as the tool, pulled your groups from AGOL.
One error I did get in my first failed attempts at using the "share package" tool, was something along the lines of "you don't have enough space left on your account" or "your account doesn't allow for this operation" or both together; I don't recall and unfortunately didn't capture it, but I only got it a few times at the beginning. After that, as shown on my results screen shot, the transfer proceeded and even "completed successfully" after a reasonable long time (slow upload perhaps), not reporting any error, only not to have the .tpk show under my contents in AGOL.
I'm hoping to gain insights from ESRI technical support.