The connection error "Did not receive file manifest reply from server" is commonly attributed to the customer's network environment. In some cases, restarting the affected local machine is able to resolve this condition.
They'll need to ensure that bi-directional traffic is permitted across ALL Silo end points using the documentation above.
If you continue to experience a connection error, please attach the session.log from the affected local machine, so we may help look for additional clues. The session.log file(s) can be found in one of the following folder paths:
You may try to access Silo using the Web Client available at www.a8silo.com if enabled for your organization.
Please contact Support if you have any additional questions and/or require further information.