# on by default from IOS-XE 17.4.1 17.3.2
voice service trace
trace
show voip trace
all = don't do this, process intense
cover-buffers = displays list of calls (cover-buffers)
# to find a call
show voip trace cover-buffer | include <calling or called number>
show voip trace cover-buffer | section <calling or called number>
# to find call detail
show voip trace call-id <call-id>
The results can be digested by https://cway.cisco.com/csa or TranslatorX. If using csa, include show run and show version to include additional analysis (dial-peer matches).