The built-in calendar in Spark works with the following calendars:
- Exchange, including Microsoft 365
- iCloud
- Outlook
For example, if you want to use your Google Calendar, please add the Gmail account associated with this calendar to Spark.
For other accounts, such as Yahoo or custom IMAP, the option to enable calendars in the settings will be greyed out.
To learn more about Spark calendars, please check out these articles: