When clicking on the "Forgot My Password" link and entering an email address in Flow the user does not get the mail notification but it is working for other users.

When this issue occurs, it might be related to any of the following scenarios:

1. The email address that the user entered has a Typo
2. The email address that the user provided Does Not Exist in Flow (not associated with a Flow user profile)
3. The email address that the user provided Exists for more than 1 Flow profile. If this option is true, a Flow PM or Admin will need to remove any duplicate emails in Flow and make sure to keep the one associated with the Flow user profile. This issue will still occur even if the profile for the other email address does not have the "Send Notification" option selected. 

Important Note: As a clue, when the issue occurs and is related to any of the above scenarios, there will not be any entries in the Flow "Mail Logs" at the time the user tries the "Forgot My Password" link.