Hi DTN,
I have just tested my FreeDigits number to Voxalot and it works fine.
The only differences I can see between your posted set up in your Voxalot account and mine are:
Host: freedigits.net
NOT proxy.freedigits.net
I have Premium Voxalot account so FreeDigits is always On Register in my account. I can't really comment on FreeDigits forwarding capabilities, their web site always seems a bit squiffy to me. I'm sure emoci will find a way to check this.
Try the Host change, if all else fails, pay the fee to Voxalot for Premium, it's worth it.
Best regards
Grahame