Processing of outbound files and messages takes place in a dialogue between the IBM Domino Server and the Cryptshare Server. For the connection between these two systems, port 443 (https/ssl/tls) needs to be open.
The clients also need access to the Cryptshare Server via port 443 in order to download incoming transfers.
Please check the network permission of the Domino server (System User). They need ports 8080 and 443 for accessing to the Cryptshare server. To obtain more accurate information on network access status, you can use under Windows the following commands: nslookup <hostname> and tracert <IP address>