Various tasks you are accustomed to perform by means of your Container (ie. accessing your web site or sending email) may fail if the corresponding services are inaccessible.
To determine the reason for problems:
1. Check if your Container is running.
To this effect, log in either as a Service Container user or as your Container root/Administrator user and look at the status bar to determine if the Container is running or down.
You can check the status of your Container via your Account Administrator Control Panel or your Parallels Power Panel.
If the Container is down, you will need to restart it.
2. Go to the System Services page on your Parallels Power Panel and check the status of the service in question. The service must be running for the corresponding functionality to be accessible.
For example, psa and mysqld must be running for the Plesk
You may also try to stop the iptables service to see if it solves the problem, because some iptables rules might prevent certain network connections.
3. Go to the Resources page on your Parallels Power Panel to determine if your Container is short of any resources. If some of the resources are marked in yellow or red, this is a hazardous situation that should be resolved immediately.