Problem with setting recurring events for Mondays

I’ve tried everything, step by step and setting an event to repeat on a Monday produces a Error 324 (net::ERR_EMPTY_RESPONSE) when trying to save the event and the event doesn’t show up on the calendar.

Please advise.

I’m running Version 1.8.3 of All-in-One Event Calendar, updating resulted in too many errors and issues, so I’m sticking with what works.

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