404 error in Default permalink setting

i have a multisite set up, in which everything about this plug in, but after posting an event, when i try to click on the event from calender or the widget, its displaying 404 error,

when i switch the permalink to DAY and name, its working, but i would like to keep my permalink to default.

any way to fix this?

https://www.ads-software.com/extend/plugins/all-in-one-event-calendar/