# Message was sent successfully but not received

Source: https://developer.nylas.com/docs/support/troubleshooting/email-not-received/

Sometimes, you might receive a [`200` response](/docs/api/errors/200-response/) from Nylas when you send a message, but the recipient never receives it. This can happen for one of the following reasons:

- [The sender's provider encountered an error](#senders-provider-encountered-an-error).
- [The message bounced](#message-bounced).
- [The recipient's provider blocked the message](#recipients-provider-blocked-message).

## Sender's provider encountered an error

In this case, the sender's email server received the request to send the message and returned a `200` response, but failed to send the message.

Nylas doesn't send messages itself when you make a [Send Draft](/docs/reference/api/drafts/send-draft-id/) or [Send Message](/docs/reference/api/messages/send-message/) request. Instead, Nylas hands the request off to the user's provider.

If you notice that a user's messages are failing to send to multiple recipients and the messages aren't bouncing, advise the user to reach out to their email administrator to resolve the issue.

## Message bounced

In this case, the sender's message bounced. They should have received a "Bounced Email" message from either their email server, or the recipient's. The bounce notification usually describes the reason that the message bounced. In most cases, the sender needs to contact their email administrator to resolve the issue.

## Recipient's provider blocked message

In this case, the recipient's provider might have flagged the message. The recipient can check their Junk folder for the message, or see if they have a filter that prevents the message from reaching their Inbox.

For more information, see Nylas' [best practices for dealing with spam](/docs/dev-guide/best-practices/dealing-with-spam/).

## Related resources

- [Check email deliverability from the CLI](https://cli.nylas.com/guides/email-deliverability-cli) — Diagnose SPF, DKIM, and DMARC issues from the terminal using the Nylas CLI.