Invalid token handling

Recently, when I did token provisioning using WiFiManager, I got an invalid token error. Luckily, I had a serial monitor which gave me the error.

This will not be true in actual deployment. I do not see error handling in the Blynk connection process. Is there a routine that is called back for “invalid token” error that can be used in code to handle this scenario? Ideally, would like to invoke the on-demand portal to capture token again showing the invalid token error.

Any pointers on how others have handled this?