In the #2738, the backtrace indicated a crash due to fixup of xlog functions while processing the parameter:
``` "$ci|end|sent subscription $hdr(Subscription-State)\n" ```
I just tested with the next line in a kamailio.cfg used with kamailio 5.5:
``` xlog("$ci|end|sent subscription $hdr(Subscription-State)\n"); ```
and it starts ok. So the problem is somewhere else, potentially a buffer overflow in completely different part of the code.
Can you list all loaded modules in your configuration (the list of `loadmodule` lines)?