Password never expires will override any password expiration policy

Enabling "Password never expires" will override any password expiration policy you configure in Group Policy.
But you can configure this setting much faster, without using dsa.msc.
To list all user accounts with "Password never expires" set:

dsquery *  -filter "(&(objectCategory=person)
(userAccountControl:1.2.840.113556.1.4.803:=65536))" -limit 0

To disable the setting for these users:

dsquery *  -filter "(&(objectCategory=person)
(userAccountControl:1.2.840.113556.1.4.803:=65536))" -limit 0 |
 dsmod user -pwdneverexpires no

(c) serverfault.com

Important:
When Basic authentication or forms-based authentication is used with Outlook Web App, the Change Password feature may not work correctly when a user uses a password that includes extended ASCII or Unicode characters. This happens because passwords that use extended ASCII or Unicode characters aren't transmitted correctly between IIS and some Web browsers. We recommend that Outlook Web App users use only ASCII characters if they'll be using the Change Password feature in Outlook Web App.