This article explains the following error that occurs when users attempt to request a password reset, and "forgotten password" emails are not sent:

Error sending email: Invalid login: 535 5.7.8 Error: authentication failed: (reason unavailable)

A log entry with the type "fn" will indicate this error during log investigation. This article provides the cause and solution for this issue.

• Forgotten password email
• Email providers
• Custom Simple Mail Transfer Protocol (SMTP) providers

Incorrect credentials were provided to the custom SMTP provider.

To resolve the email sending issue:

1. Update the credentials for the custom SMTP provider with the correct details.
2. Attempt to resend the email.