Failed means the send attempt (SMTP or Amazon SES) did not report success; Sent means it was accepted for delivery (it does not guarantee it reached the inbox). The Email Log does not store a specific error message for a Failed row - only the Sent/Failed status - so the underlying cause has to be worked out from context. Things to check:

• Protocol shows 'default' - no sending method is actually configured on the server for that email (neither SMTP nor SES environment settings are in place); contact Sprwt support.
• SMTP credentials wrong or expired (for example a Gmail app password revoked), or an Amazon SES address that isn't verified - ask Sprwt support to check the SMTP/SES settings.
• Recipient address malformed - check the To column.

After fixing the cause, re-trigger the action (for example resend the password reset); failed emails are not retried automatically.