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500-599 Response

500 responses return when there is an error on the server side.

500 - Server Error

Cause
An error occurred in the Nylas server.

Solution
If this persists, see our status page.

502 - Server Error

Cause
An error occurred in the Nylas server.

Solution
If this persists, see our status page.

503 - Service Unavailable

Cause
There was an error connecting to the user's mail provider.

Solution
Wait and try again later.

503 - Server Unavailable

Microsoft

Error 503’ Throttle Header, 'X-MS-ASThrottle: CommandFrequency

Cause
There are too many commands.

Solution

  • Managed Exchange accounts should contact the administrator to increase the threshold for CommandFrequency.
  • The default value for CommandFrequency is to block after 400 commands in 10 minutes. Block for 20 minutes.

503 - Server Error

Cause
An error occurred in the Nylas server.

Solution
If this persists, see our status page or contact support.

504 - Server Error

Cause
The action timed out making an external request.

Solution
Please try again.

550 - Service Unavailable

The message was classified as spam and may not be delivered.

Cause
Some email providers review all outbound emails through their spam filter before sending, to preserve their email-sending reputation. Spam filters work by comparing emails to an extensive list of matching behaviors and giving each behavior a score. We return that the email was blocked for spam in the API response, but we don't have any visibility into exactly what caused the block.

Solution
Take a look at our docs on Dealing with spam.