1) Do not allow departments to have extensions that forward to each other. (sales: 100, 101, 102; where 100 also fwds to 101). Additionally Do not allow extensions to forward to each other if they belong to the same department already. Can cause call failures.

2) In R! admin > Phone Numbers, DO NOT allow a client to 'save' when both
Use these Hours For this Phone Number > Send the after hours calls to > "Use the Voicemail and Callback Preferences" is SET
AND a MENU is selected as the 'Send Calls To'
Causes afterhours calls to immediate hangup. (unless that's the intent)