Ricardo,
My name is Ismael. Iam with Small Business Support center and do appreciate you reaching out to us. From what you have described to us is that you having issue with port forwarding with RDP (3389). I am also understanding that you have a Modem/router combo from ISP and then the RV016.
For port forwarding to work, you need two rules one on your modem/router and one on your RV016 . So its source ip address will be the LAN of this modem and destination is WAN ip address of the RV180. Another rule is then configured on RV180 WAN pointing to LAN of the internal device you trying to reach. So its source ip will be the WAN on RV016 and destination will be LAN ip address of the internal device you trying to reach. This type of double port forwards can be complex and unstable. So if your network allows for configuration changes then you modem can be set to bridge mode, to simplify things and have them working for you all the time.
The single port forward can still be done, but it would require for your ISP to fully bridge your Modem. This will allow for RV016 to receive a public ip on WAN1. Once bridged only one rule is required on your RV016. Hope this helps you.