[ibr-dtn] DTN bundle rejected issue

Hello,

I'm trying to do a dtnping between two dtn nodes I have, I have noticed that they can see each other, however, when I try to make a ping from node 2 to node C, I get this warning :

*Mon Mar 4 13:49:45 2013 WARNING: bundle rejected: bundle has expired ([415720186.377] dtn://node2.dtn/zsKZSPktexxyNvJ -> dtn://nodeC.dtn/echo) Mon Mar 4 13:49:45 2013 WARNING: bundle has been rejected: bundle is expired*

I see the packages is discarded, but I cannot understand the reason, is it due to a bad synchronization among the clocks of the devices? How may I resolve it?

Thanks in advance,

regards!