Thank you. My coworker found the fix, by looking at other scripts.

18c18
< my $ldap = Net::LDAP->new($dc, port => 636, scheme => 'ldaps') or di
+e "$@";
---
> my $ldap = Net::LDAP->new($dc) or die "$@";
[download]

i.e. reduce the parameters to the LDAP constructor. *shrug*