# 35115: Scheduling does not support this timestamp

Log Type: APPLICATION

Log Level: ERROR

## Description

This error occurs when `SendAt` falls outside the supported window for a scheduled message. Set `SendAt` to a UTC ISO-8601 timestamp that is more than 5 minutes (300 seconds) from the request time and no more than 35 days in the future.

### Possible causes

* `SendAt` is less than 5 minutes from when Twilio receives the request.
* `SendAt` is more than 35 days in the future.
* You created the timestamp too close to the minimum lead time, and application delay pushed it out of range before Twilio received the `POST` request.
* `SendAt` is not in the expected `YYYY-MM-DDTHH:MM:SSZ` format in UTC.

### Possible solutions

* Update `SendAt` so it is more than 5 minutes (300 seconds) from the request time and no more than 35 days in the future.
* Send `SendAt` as a UTC ISO-8601 timestamp in `YYYY-MM-DDTHH:MM:SSZ` format.
* If you schedule close to the minimum allowed time, add buffer before you send the API request so Twilio receives it within the supported window.

#### Additional resources

* [Message Scheduling](/docs/messaging/features/message-scheduling)
* [Messages resource](/docs/messaging/api/message-resource)
* [Messaging API Overview](/docs/messaging/api)