Calendar not sync between device

What I did: I bought the premium for macos and ios and use across all device: my macbook, my phone, my iPad

What happened: the calendar added by gmail to my iphone calendar and shown in Agenda iPhone, not shown in Mac and ipad

What I expected: all sync all device for note, calendar, reminder

Things that might be helpful to know (Agenda version, OS and model, etc):

Macbook air
iPad pro 11
Iphone XS Mas
all ios update to lastest version

Make sure your Google calendar appears in Apple’s calendar on Mac and iPad. You may have to add it there.

If it appears in Apple’s apps, it will also appear in Agenda (after you give permission).

Kind regards,
Drew