chan_sip.c:1786 __sip_xmit: Bad file descriptor

Hi to all,
Hop you all will be fine. I want to ask that when i start my asterisk it gives me warning like this

[Nov 11 17:44:01] WARNING[10248]: chan_sip.c:1786 __sip_xmit: sip_xmit of 0x8ab7e18 (len 582) to 116.71.51.138:51009 returned -2: Bad file descriptor
[Nov 11 17:44:15] WARNING[10248]: chan_sip.c:1786 __sip_xmit: sip_xmit of 0x8a6d918 (len 580) to 116.71.46.44:55950 returned -2: Bad file descriptor
[Nov 11 17:44:15] WARNING[10248]: chan_sip.c:1786 __sip_xmit: sip_xmit of 0x8a6df18 (len 580) to 116.71.34.35:34620 returned -2: Bad file descriptor
[Nov 11 17:44:15] WARNING[10248]: chan_sip.c:1786 __sip_xmit: sip_xmit of 0x8ab7998 (len 582) to 116.71.38.8:59126 returned -2: Bad file descriptor
[Nov 11 17:44:15] WARNING[10248]: chan_sip.c:1786 __sip_xmit: sip_xmit of 0x8ab7e18 (len 582) to 116.71.51.138:51009 returned -2: Bad file descriptor
can any one tell me why this warning is coming and how can i handle it.
Thanks in advance