You don't need to embed the calendar view using embed web part anymore as SharePoint online out of the box List web part now supports showing modern calendar list view.
Check detailed steps to add Modern Calendar view to a SharePoint Online page using List web part at: Add Modern Calendar to a SharePoint Online page using List web part
This feature is currently rolling out to targeted release tenants. You can check the roadmap of this feature at: SharePoint: Calendar view in Lists web part
If you want access to this feature earlier (before general availability / standard release), you can set targeted release in your tenant: Set up the Standard or Targeted release options
Else, if you want to continue using embed
web part until the feature is available generally, you can try settings src
attribute of iframe
to absolute URL of calendar view in below format:
https://tenant.sharepoint.com/sites/siteName/Lists/ListName/ViewName.aspx
Example:
<iframe src="https://<tenant>.sharepoint.com/sites/siteName/Lists/ContentScheduler/Calendar.aspx" width="100%" height="600"></iframe>
Follow this article for detailed steps: Add Modern Calendar to a SharePoint Online page