Plesk web interface blocking mechanism?

[breun]

A client encountered a problem while disabling an autoresponder. The Plesk web interface would hang after clicking the button to perform the operation and the Plesk web interface became inaccessible (would not load) after that. For others the Plesk web interface was still available.

I was able to reproduce this problem and it also happened while creating a new mailbox. However, I was able to disable the autoresponder through the Plesk autoresponder command line tool. I'm not sure if the problem is limited to mail operations, but my real question is: is anyone aware of any form of blocking mechanism in the Plesk web interface that could be the cause of not being able to reach the Plesk web interface after triggering the problem? I haven't been able to find any information on such a mechanism.