Sync Sbcglobal.net/Yahoo calendar to Android Note 4

I use yahoo calendars with my Sbcglobal e-mail account.  I have recently changed to an Android phone (galaxy note 4).  I am having issues syncing the calendars with the phone.  I have tried several calendar apps and sync interfaces.  It sees all of the calendars, but I have noticed on one calendar that not all of the events are showing up.  I looked to see if it was not seeing just the repeating or individual calendar events, and there is no logic to what is not showing up.  This is critical if I add something on the web based calendar and does not show on the phone.