We have a Cisco Model ISR4321/K9 router with Cisco IOS XE Software Version 16.09.04
The problem occurs when we make a call forward to an external number.
The call made by User A to the destination User B (user B has activated a call forwarding to another external number User C)
User C answers the call, user C does not hear anything, User A does not hear anything either, but after 18 seconds the call closes automatically by itself.
User A -->+49xxxxxxx90 ...incoming call
User B--> +49xxxxxxx55 --> call forward to User C
User C--> +49xxxxxxx30 .....Extern number ( external forwarding is configured on the router)
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voice service voip
no notify redirect ip2ip
address-hiding
allow-connections sip to sip
no supplementary-service sip moved-temporarily
no supplementary-service sip refer
fax protocol t38 version 0 ls-redundancy 0 hs-redundancy 0 fallback pass-through g711alaw h323
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voice register global
mode cme
source-address 172.20.XXX.XX port 5060
max-dn 10
auto-register
!
voice register dn 2
number +49xxxxxx55
call-forward b2bua unregistered +49xxxxxx30
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Can someone help me to solve this problem
BR ,
Anibal