ISSUEWhen replying to a Lazy Approval email with a valid outcome the email does not seem to be received by the O365 tenant and the Task remains in the status of Not Started.
RESOLUTIONThere are many reasons why this issue can occur but these are the basic things to check.
1. Navigate to the Nintex status page and check for any incidents concerning Lazy Approval.
2. Make sure that the Email infrastructure is not changing the domain for outgoing emails as the task can only be completed if a reply is received from the email address that it was sent to.
3. Make sure that the Email infrastructure is not altering the subject line of the email and altering the Lazy Approval token.