4452d530_able___FreeSWITCH___Confluence__Description
[ITU-T Q.850 Code] 38 [SIP Equiv.] 503 [Enumeration] NETWORK_OUT_OF_ORDER [Cause] network out of order [Q.850] [Description] 
This cause indicates that the network is not functioning correctly and that the condition is likely to last a relatively long period of time e.g. immediately re-attempting the call is not likely to be successful.
Hangup Cause Code Table - FreeSWITCH - Confluence
Description