Start by finding the call UUID of each participant in the conference call. You can find a call UUID through the console at Voice > Logs. Click on the timestamp of the call you want to debug to see the call UUID.
Alternatively, you can use the Call method to request call detail records (CDR), which include call UUID information.
Use the call UUID
After getting the call UUID, navigate to https://console.plivo.com/voice/logs/debug/ and enter the call UUID in the search field. This will surface call details like these:
You can also check the XML document used on the call to handle the call flow to debug the call.