To use the Myo armband with any application, it must connect to Myo Connect.
If that connection is blocked by another application or service such as a firewall or antivirus, the application will not be able to communicate with Myo Connect, resulting in an error. This can be in part of a protocol filtering service such as one in ESET Nod32 Smart Security and Antivirus.
Adding an exception in the application/service that is blocking the connection is required to use the Myo armband. Other applications that may block the connection are Lavasoft Ad-Aware Free Antivirus and Antispyware, Avast Antivirus.
If you are still unable to connect to Myo Connect, please email email@example.com.