Why are messages and notifications sent to an old email address?

This may indicate that you have an older email address entered in your Alert settings. If you change the primary email address on your account, you would need to update the email address in your alert settings separately. 

If you log into your HowDidiDo account and go to Profile > Alerts then please ensure the correct email address is entered here:

If it is the old email address then please update the email and save and this should resolve the problem.