Twilio offers several tools for investigating the interaction between Twilio and your application. If a message fails to go through, is delayed, or otherwise behaves unexpectedly, these tools should be your first stops for debugging.
How to navigate to the Messaging Logs and how to use them?
You can view the error logs for your Twilio account by going to the Twilio Console. You can use this log to get an idea of which Twilio resources may be affected and who was responsible for them.
Log on to Twilio https://console.twilio.com/
Go to the top right -> Click Account -> Click Subaccounts
If there are too many subaccounts inside Twilio, you can go back to HL and copy the Account SIN for that location to search in Twilio:
Now go back to Twilio with the copied Account SID
Search based on the Twilio Subaccount SID in agency level settings -> Twilio
Paste the Account SID here and click on it:
Once you are in the subaccount inside Twilio
Head to the Left panel, Click Monitor > Logs > Calls

Put the contact's phone number (remove all phone format) in the FROM / TO field:
FROM field: Plug Contact's phone in the to field to check for incoming calls
TO field: Plug Contact's phone in the to field to check for outbound calls
From there, look for the Call where the problem happened. Click the hyperlinked dates to go deeper into the details for each call.