[Serusers] Register Signal corrupted

All, I got a weird problem for Grand Stream 486 ATA registering on my ser server. Server in in US and ATA is registering from India. Here is ngrep trace. Every time the device tries to register the "Register" word get some extra characters. For example in this case REGISTER became R:50145EGISTER and ser replies with 404 User Not found. Anyone faced this issue, any idea how to debug/fix this problem this. U 59.180.68.3:50145 -> XXX.XXX.XXX.211:5060 *R:50145EGISTER* sip:XXX.XXX.XXX.211 SIP/2.0..Via: SIP/2.0/UDP 59.180.68.3:50146;branch=z9hG4bKbd52be32ad52bf32..From: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>;ta g=e5ca733921001365..To: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>..Contact: *..Supported: replaces, timer..Call-ID: 53fb73fb244b57b9@192.168.1.4..CSeq: 100 REG ISTER..Expires: 0..User-Agent: Grandstream HT487 1.1.0.26..Max-Forwards: 70..Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDATE..Content-L ength: 0.... # U XXX.XXX.XXX.211:5060 -> 59.180.68.3:50146 SIP/2.0 404 User Not Found..Via: SIP/2.0/UDP 59.180.68.3:50146;branch=z9hG4bKbd52be32ad52bf32..From: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>;tag=e5ca73392100 1365..To: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>;tag=2d30881a84b19f18b705d17dbf895433.1f56..Call-ID: 53fb73fb244b57b9@192.168.1.4..CSeq: 100 REGISTER..Serve r: Sip EXpress router (0.9.6 (i386/linux))..Content-Length: 0..Warning: 392 XXX.XXX.XXX.211:5060 "Noisy feedback tells: pid=7507 req_src_ip=59.180.68.3 req_src_ port=50145 in_uri=sip:XXX.XXX.XXX.211 out_uri=sip:XXX.XXX.XXX.211 via_cnt==1".... ### U 59.180.68.3:50145 -> XXX.XXX.XXX.211:5060 R:50145EGISTER sip:XXX.XXX.XXX.211 SIP/2.0..Via: SIP/2.0/UDP 59.180.68.3:50146;branch=z9hG4bKbd52be32ad52bf32..From: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>;ta g=e5ca733921001365..To: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>..Contact: *..Supported: replaces, timer..Call-ID: 53fb73fb244b57b9@192.168.1.4..CSeq: 100 REG ISTER..Expires: 0..User-Agent: Grandstream HT487 1.1.0.26..Max-Forwards: 70..Allow: INVITE,ACK,CANCEL,BYE,NOTIFY,REFER,OPTIONS,INFO,SUBSCRIBE,UPDATE..Content-L ength: 0.... # U XXX.XXX.XXX.211:5060 -> 59.180.68.3:50146 SIP/2.0 404 User Not Found..Via: SIP/2.0/UDP 59.180.68.3:50146;branch=z9hG4bKbd52be32ad52bf32..From: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>;tag=e5ca73392100 1365..To: <sip:1004613554@XXX.XXX.XXX.211;user=phone> <sip:1004613554@XXX.XXX.XXX.211;user=phone>;tag=2d30881a84b19f18b705d17dbf895433.1f56..Call-ID: 53fb73fb244b57b9@192.168.1.4..CSeq: 100 REGISTER..Serve r: Sip EXpress router (0.9.6 (i386/linux))..Content-Length: 0..Warning: 392 XXX.XXX.XXX.211:5060 "Noisy feedback tells: pid=7522 req_src_ip=59.180.68.3 req_src_ port=50145 in_uri=sip:XXX.XXX.XXX.211 out_uri=sip:XXX.XXX.XXX.211 via_cnt==1"....