Hi Everost,
I have reviewed the article you provided. According to the article, I know you set up a shared calendar via public folder(calendar items).
From my experience, you can open the public folder via the steps below in OWA:
1. Login to the OWA(https://outlook.office365.com/owa/).
2. Right-click Favorites> add public folder.
3. Select the public folder and click add.
Unfortunately, it only supports mail enabled public folder in OWA now. You cannot view Calendar items. In this situation, I recommend you submit feedback (click on the hyper link) to our product feedback collection team. Many features of current programs have been designed and upgraded based on customers’ feedback. Thanks for your understanding.
In addition, you could follow the steps below to view the shared calendar in Outlook 2011 for Mac:
1. In Outlook 2011 for Mac, in the ribbon, select Tools tab, then click on Public Folders.
2.In Folder Browser window, navigate through the public folders tree until you locate the folder you need to access. Highlight the public folder, then click Subscribe.
3.Open Calendar in your Outlook 2011 for Mac. Under the Subscribed Public Folders you will see the list of public folder you subscribed to.
If you have anything unclear, please feel free to let me know.
Thanks,
Kid Yang