I FINALLY found how to fix this problem! Go into the Outlook365 app on Samsung Android phone. It will take wherever you have Outlook365 set to open (mine is email), press calendar button at the bottom of screen to go to Outlook365 calendar. Next press Outlook365 icon at the top left of screen, which will list your Outlook365 calendar and maybe your workplace acct. or birthdays, etc. if you put those in. PRESS SETTINGS AT THE BOTTOM LEFT OF YOUR SCREEN. In mail accounts press Outlook365, which opens a screen that shows sync calendars as OFF. Obviously, switch to ON, and when you resync your Samsung calendar it will have your Outlook365 calendar back and synced!