Asterisk crashes on Transfer function with tel: URL

[kumarunster]

thanks for your thoughts

finally, after days of try and errors I found working configuration for my case. The key was to answer the call first

here is rough config, maybe someone will find it usefull.

extensions_custom.conf:

[external-transfer-out]
exten => s,1,Answer(i)        
same => n,transfer(PJSIP/sip:+49XXXX09@amXXXsipzentrale.pstn.frankfurt.twilio.com)

custom destination (FreePBX: Admin/Custom Destinations)

Name: internal_to_external
Target: external-transfer-out,s,1

Extensions
FreePBX/Applications/Extensions/Find Me Follow Me
Destinations
No Answer → Custom Destinations → internal_to_external
FreePBX/Applications/Extensions/Advanced
Optional Destinations
No Answer, Busy, Not Reachable → Custom Destinations → internal_to_external

[kumarunster]

it is not the solution for the topic, asterisk will still crash on misconfiguration (which maybe should not happen), but for me, it works for now as expected.