Using New Outlook on Windows for professional communication and productivity
Hello, since it is less than 10, you will have to wait for 7 days to be able to add more alias. Here are some alias rules below:
Rules for adding an alias are
1 - A maximum of 2 alias addresses can be added within a rolling 7 day period. to add more you need to wait for 7 days
2 - A maximum of 10 active alias address can exist on an account
3 - A maximum of 10 alias addresses can be created within the previous rolling 12 month period
Please let me know if you need further assistance
Best Regards
Femi S.