Are there any reference for error codes of Telegram Bot API? – Telegram API

From Telegram Bot Api documentation page:

The response contains a JSON object, which always has a Boolean field ‘ok’ and may have an optional String field ‘description’ with a human-readable description of the result. If ‘ok’ equals true, the request was successful and the result of the query can be found in the ‘result’ field. In case of an unsuccessful request, ‘ok’ equals false and the error is explained in the ‘description’. An Integer ‘error_code’ field is also returned, but its contents are subject to change in the future.

Whenever you make a request check if it succeed so you are sure if a certain chat_it is still valid.