A Snowflake stream can become stale if its offset moves outside the data retention period for the source table/view.
Review the Snowflake document Avoiding Stream Staleness on how to avoid a stream becoming stale
A stale stream can be identified through the query history as shown in the example below
To un-stale a stream, simply rerun the create statement making sure that the grants to it are the same as prior to the recreation
Overview
Content Tools