The most likely reason far a Communication Error:”SOAPservice is undefined” when logging in to your account from an Ftax form is that your version of Windows is not using the correct TLS (Transport Layer Security) version.
Ftax forms require TLS 1.2 to be available for use.
TLS settings are handled via the Advanced tab of the Internet Properties (or Internet Options) dialogue box.
To open the Internet Properties (or Internet Options), press the start button and start typing Internet Properties (or Internet Options) and Windows will show you the control panel to open.
Once open, click the Advanced tab at the top:
Please make sure that your system has TLS 1.2 version ticked, click the OK (or Apply) button and try again.