In order to fix the issue, go to Start, type Windows Firewall and open the utility. Press the Allow a program through Windows Firewall option, check the box next to SoftDA and click OK.
After that, from the Advanced Settings select Inbound Rules > New Rule. Check the Port box, click Next, select All local Ports and follow the self-explained steps.
Also, make sure that your security program doesn't block the connection. If the error persists contact the developers because the SoftDA servers may be temporarily down or under maintenance.
