Access Denied error when trying to add event

Hi.

I am a new user to Ajax Event Calendar, so forgive me if I am missing the obvious, but when a registered user tries to Add an Event using the Add Event button on my Calendar page, they receive the error “Access Denied. Your site administrator has blocked your access to the WordPress back-office”

The user has a defined role of Calendar Contributor, and the group for this set of users being protected using User Access Manager plugin version 1.2.5.0 has a role affiliation of calendar co-contributor as well.

Here is my website:

https://www.greenoughharbourcommunity.ca

Thanks

https://www.ads-software.com/plugins/ajax-event-calendar/