The softphone cannot forward the call if the account is not in service. To make this work, configure the server that handles call routing to allow automatic forwarding calls if the account is unreachable or fails to answer within a specific time.
If the forwarding account is not in service, the app cannot forward the call because it relies on the account being accessible. However, this can be managed by a server that handles calls and call routing. For example, the server can be set to forward calls automatically if the account is unreachable or does not answer within a specific time or number of rings. This setup is similar to how voicemail works, but it needs to be managed on the server side.