Issue of null Agent status

I am facing an issue of null Agent status, when i check Agent real time Status using CLI command “Show Agents”.
Again after 1 or 2 mins,every thing is normal.

what is a dead Agent status ?

How can i trouble shoot it ?

Please help

Please provide the actual console output, and the Asterisk version. There is no literal string “dead” in the 1.8 version of chan_agent.c, so I don’t know how that version could produce output containing the word “dead”.