autoconfig and autodiscover is always configured by default, you don’t have to add those.
As an example: you added DNS entries for
autoconfig.domain2.tld
autodiscover.domain2.tld
mail.domain2.tld
webmail.domain2.tld
and configured
ADDITIONAL_SAN=mail.*,webmail.*
then your certificate will contain all 4 SANs from above + the ones from domainX.tld