Which URL does work as "Related space" when creating a calendar

[Mai Tanno]

I am now trying to create a calendar in my confluence page.

I have created calendar in 'My Calendar', and would like to show it in other confluence page.

However, I enter the confluence page url in "Related space"but error occurs and cannot save.
Could you please tell me which kind of url would work instead?

<Reference page>

https://confluence.atlassian.com/doc/create-add-and-edit-calendars-1044780370.html