Modem/ppp takes 3-4 attempts to connect (56kbps dialup)

[Ben Washington-Yule]

Hi all.

For no apparent reason when I type 'ppp -ddial xtra' the modem clicks 
on, starts dialing, disconnects for some reason, clicks off, starts the 
process again. It does this about 3-4 times before it connects if it 
even connects at all. I have tried to figure this one out myself, I've 
scanned the ppp log which made no sense to me (the only error I saw was 
'No response from server'). What commands can I use to diagnose this? 
What does this problem sound like?

Connection:
56kbps dialup, dynamic IPs, XTRA NZ.

I can post my ppp.conf if you think it's needed. Cheers, Ben.