Error Message :
The input must be minimum 1 and maximum 100000
Using the Automic Web Interface (AWI) version 12, a message appears when trying to set the Queue slot value to 0 as shown below.
<Please see attached file for image>

This contrasts with the Java User Interface, where it is possible to set the maximal Queue slots to 0 to prevent new tasks from executing in that queue without stopping it.