Not ACKED message found, will retransmit. SENT...

[gerandong]

hi,

i have warning for smpp sending,

WARNING: SMPP[*****]: Not ACKED message found, will retransmit. SENT<90>sec. 
ago, SEQ<71>, DST<6*****9>

then the sending is about 1minute / msg :((
and store file is big.

please help...

thanks

gerandong