If you see this error on the title of the page, it means the site is over its bandwidth allocation. For Resellers and Multiple domain clients, to fix this please do the following:
Please log into your webhost manager and create a new package (one that has higher bandwidth limit). Then click on the upgrade/downgrade an account option. Select the domain that is showing the error, then select the new package you just created. Finally, click on limit bandwidth to make sure that the bandwidth limit has been updated. To confirm the immediate change, click on the change button and you are all set.