Environment

GroupWise 24.x

Situation

When you have set a size limit overwrite for certain users and these users have a nickname the limit is used when sending to the userID but not when sending mail to the nickname of this user

The setup used is a "default class of service" with a size limit of 1000KB 
A second class of service created for a few users that can receive mail larger then this with a size limit set to 2000KB 

Create a nickname for the user so you can mail to userID@company.com and nickname@company.com

When sending a message with the size of 1500KB it is accepted by the GWIA when sending mail to userID@company.com
When sending a message with the size of 1500KB it is denied when sending to nickname@company.com

See full knowledge document here