If you are receiving this error, it is because input in your Silo session was not detected within a certain period. If you are an individual using Silo, you will receive this message after 30 minutes of inactivity. If you are part of an organization, then these timeout sessions are set by your organization. The max timeout time that can be set by an organization is 4 hours.
Please contact Support if you have any additional questions and/or require further information.