Connect nextcloud to exchaange error "using 0 possible authenticators"

hi everyone

we have nextcloud 20.0.4 appliance and want to connect it to exchange in Email server setting.
we use setting in attached image as bellow and get error :

“A problem occurred while sending the email. Please revise your settings. (Error: Failed to authenticate on SMTP server with username “xxxx@yyyy.com” using 0 possible authenticators”