Today a customer notified me that their web site was not coming up.. They had no outstanding payments, they hadn't exceeded their quotas. In ISPCONFIG, the "active" box was simply unchecked. I checked it back and their web site resumed operations. I didn't get any notifications in the mail that they were being suspended, etc. Any ideas why it could go into inactive by itself?
Most likely you set a traffic limit, and this traffic limit was reached. Increase the traffic limit or disable the traffic limit by setting it to -1.