[Asterisk-Users] I can't call PSTN numbers

[Sebastian Milioto]

Hi all,

I hava SER with many clients (sipura SPA2100). One of these is an
Asterisk which have others clients (sipuraSPA2100).
I also have a Cisco GW which give me access to the PSTN.
I make calls to all IP phones in my network, but I can't call PSTN
numbers. After I dial, I hear 2 ringbacks but at the same time
Asterisk says:

Called pstn_number at SER_ip_address
SIP/SER_ip_address-ec75 is circuit-busy
Everyone is  busy/congested at this time (1:0/1/0)

Then I hear busy tone.

I tried thousands of parameters. (Ovbiously not the correct one :-s )
Any body could help me with this?

Thanks very much in  advance

Sebastian