I tested it with manual Nextcloud 20.0.4 on Debian 10 using NethServer LDAP and it’s working with port 636 but I needed to set at least the “Group Member association” to “memberUid” in the “Advanced” tab:
I tested it with manual Nextcloud 20.0.4 on Debian 10 using NethServer LDAP and it’s working with port 636 but I needed to set at least the “Group Member association” to “memberUid” in the “Advanced” tab: