Problen with remote connection

[Sejoita]

We cant connect wit a bp 50.The log errors have 25:system error and 50:no tr-process found,the code of error refers to the SN(number of signal).
The trace of the operator :

Q.931 Call Control Message
7B Call Reference Value Orig 123
M 7D Message Type STATUS
I 08 Cause Length = 3
82 Coding Standard CCITT
Location Local Public Network
E4 Class Protocol Error
Value #100, Invalid Info Element Contents
Diagnostic Info Element ID
4C Info Element Connected Number
I 14 Call State Length = 1
08 Coding Standard CCITT
Value Connect Request
------------------------------------------------
Event 6 10-05-06 18:10:00.54 TEI 0
08 Q.931 Call Control Message
7B Call Reference Value Orig 123
M 0F Message Type CONNECT ACKNOWLEDGE
------------------------------------------------
Event 7 10-05-06 18:11:03.07 TEI 0
08 Q.931 Call Control Message
7B Call Reference Value Orig 123
M 45 Message Type DISCONNECT
I 08 Cause Length = 2
80 Coding Standard CCITT
Location User
90 Class Normal Event
Value #16, Normal Call Clearing
I 1E Progress Indicator Length = 2
82 Coding Standard CCITT
Location Local Public Network
88 Value In-band Information/Pattern Avail

We can see a protocol error and them make a normal call clearing disconnecting the modem.It is due to a line or the central?the central have the same trunks configuration like others clients and in some works correctly.

Trace operator attached.

Thanx for help