[Freeswitch-users] Phones become unreachable after some time

[paul.degt]

I use FS 1.0.3 with Grandstream HT386 and X-Lite soft phones, FS binds 
to Mysql DB for SIP registrations, presence etc.
I noticed that after some time probably >30 min. phones which have been 
registered but without making calls become unreachable. Meaning that any 
call to such extension gets forwarded to VM as if it was offline, until 
I reload such phone.
I did try to make the phones to register every 5 min. but it does not 
help. I also see valid registration information in sip_registrations 
table. X-Lite has r-port and keep alive settings on.
Would appreciate any hints on what can be the issue here.