Question : mail enabled security group does not appear in Global Address List

I have created a mail enabled Global Security group but it doesn't show in the global address list when I try to email to it from Outlook. I have checked the properties of the group and 'Hide Group from Exchange Address Lists' is unchecked.

Any ideas

Answer : mail enabled security group does not appear in Global Address List

cisco 1841 is comming default with 64Mb flash and 256 Mb ram and IP BASE, 12.4(15)T

so it can be upgraded to c1841-advipservicesk9-mz.124-12.bin that required only
minimun 128MB ram and 32 MB flash