Asterisk Uptime

i have a problem that i’m using freebpx ver 2.5.1.0 and every time i check i found thta the
Asterisk Uptime time change for examble last Asterisk Uptime 5 hours then change again to be 1 second and so on , when the Asterisk Uptime change all call disconnected and this make a hug problem cause i’m using this server for Call Center agents so please i need your advice

You have a problem with your setup. If Asterisk crashes it will restart again and that is why you get a new Asterisk Uptime.
Please check the log files for Asterisk in /var/log/asterisk