From the following link, it appears you cannot have Home & Away voicemail (or regular voicemail?) and utilize Call Forwarding. Yes, it certainly is confusing, but it appears that voicemail is the issue, also outlined as a condition in the link in the post above:
https://www.rogers.com/customer/support/article/what-is-home-away-online-manager-and-how-do-i-access...
Forward All My Calls - Forward your calls to an alternate number when you’re away from your home phone.
Forward Friends & Family Calls - Set up a list of friends and family contacts, and forward calls from the list to your mobile phone or office line.
Forward Busy & Unanswered Calls - Whenever your home phone line is busy or nobody picks up, incoming calls will be forwarded to a number of your choosing.
Keep in mind: This feature is only available if you don’t subscribe to Home & Away voicemail.
The way I read it, you can't have voicemail and call forwarding at the same time.