I only have one Gmail account.
I think the choice of calendars is the culprit and I found it easier to work with the previous android upgrade, not marshmallow, to choose the right one.
On the c I click Chrome then click the dots in a square upper right, I then choose Google calendar.
I then go to my phone and click on the Google calendar. I sign in to both but although the stock and google on the phone sync, the PC does not.
I am unsure as to how to "pull in" the calendar.