Tvheadend

Hi. I use Tvheadend version 3.9.2514,Ubuntu 14.04
Some muxes not detect streams on iptv.
During the scan on statustab show bandwidth (~3500kb/s),
but then in system log on some channels:
2015-02-26 11:13:30.000 mpegts: FOX in IPTV network - scan no data, failed
2015-02-26 11:13:30.000 subscription: 0001: "scan" unsubscribing

Working muxes and non-working have a identical parameters (below)
For example:
udp://@239.2.100.154:4321 - non-working
udp://@239.2.100.112:4321 - working

Without TVH both channels work fine.

Both channels have same settings:
Stream 0
Type: Video
Codec: MPEG-1/2 Video (mpgv)
Resolution: 720x576
Frame rate: 25
Decoded format: Planar 4:2:0 YUV

Stream 1
Type: Audio
Original ID: 8002
Codec: MPEG Audio layer 1/2/3 (mpga)
Language: Russian
Channels: Stereo
Sample rate: 48000 Hz
Bitrate: 192 kb/s

Stream 2
Type: Audio
Original ID: 8003
Codec: MPEG Audio layer 1/2/3 (mpga)
Language: English
Description: clean effects

P.S. Sorry for bad english