Archicad must be able to communicate with BIMcloud / BIMcloud Basic to provide Teamwork. To verify this, run the Network Diagnostic Tool from the Open / Join dialog or the Teamwork Palette. Verify whether all necessary ports are open and the server machine is available from the client machine. If you still experience the above issue, please contact your GRAPHISOFT support representative. During the investigation Archicad FastLogger files might be necessary. See the Archicad FastLogger Files article for the location.