Today when you set up a connection to Sharepoint it is only valid for 90 days. After 90 days if you don't manually refresh the data-connection you get the error "The refresh token has expired due to inactivity". The connection is active though and retrieves data everyday. But the refresh-token hasn't been updated.
The limit of 90 days is set by Microsoft, but it should be possible to make an update of token automatically without the need for a user to manually update the data-connection.
My suggestion is that the Sharepoint-data connection handles this.