I'm getting alert message "Your routing backup limit is 1. When you exceed this limit, last backup will be replaced with a new one."

You can make a backup copy of your SSD Cloud Servers at no additional cost. However, each time you schedule a new job or execute a manual backup, the last backup will be replaced with the new one.
Please also note that backup is not refreshed and stored more than 30 days will be removed.
Additional Backup jobs and number of backup is an additional add-on for SG$10 monthly each and up to 7 copies you can order during or after the initial order.