In the case you encountered email sending error “Unrouteable address” , it is highly due to one of the account in your domain was compromised thus using up the email sending quota. Error message as below:
How to check which email is compromised?
1. Login to your Direct Admin
4. The email account that been sending out most email will be shown. The account shown is likely be compromised. Please change the user password immediately to prevent him from sending spam and using up quota again.
How to mitigate this issue from happening?
We strongly encourage you use strong and complex password for all email account, Eg. $1wQ#$g0R
Note & Options:
1. In order for you to send out email again, you can either wait until tomorrow for the quota to be reset again or choose to upgrade mail services.
2. If you can’t wait and need to send email immediately, you can subscribe our Smart Hand services which cost RM100.