Do you have any filtering set up in the software for your sound card/controller?
The no signal icon indicates the speech recognition engine isn't hearing anything (not even background noise), which likely means something is filtering out that background noise, and potentially distorting or attenuating the signal enough to affect speech recognition.
Try disabling the "VOLUME NORMALIZATION" and "AMBIENT NOISE REDUCTION" options in Razer Synapse, if you have them enabled (and any other filters, should they exist).
Also try checking the "Disable Acoustic Echo Cancellation (could help with recognition)" option on the "Recognition" tab of the VoiceAttack options window, if you haven't already.