1.First you need to be logged into your Plesk in your admin account.
2.Browse to Home (on the left side of the screen).
3.Select Suspend/Unsuspend Domain under the Domains section.
4.The last action will display the list of domains on the server. The domains that could be unsuspended will be having a red x next to them. Select the check box of to the domain that you wish to change, and then click Finish.