Reconfigure Prosody on moschatum
Pups requires the "mod_auto_accept_subscriptions" Prosody module. This is required for checking if a support assistant is currently available to speak with users.
The mod is available through hg at https://code.google.com/p/prosody-modules/wiki/mod_auto_accept_subscriptions, or it can be downloaded directly from http://insecure-complexity.ca/mod_auto_accept_subscriptions.lua.
Installing is done by grabbing the extension from one of the above locations, and dropping the file into /usr/lib/prosody/modules. Once it is installed, it can be enabled by adding '"auto_accept_subscriptions";' in the "modules_enabled = {" section of the Prosody config (/etc/prosody/prosody.cfg.lua).