RV325 - Port forwarded but still closed

[randrade86]

We have a RV325 (192.168.63.1) router behind our TP-Link router (192.168.0.1), in a pretty simple setup. 

RV325 is also the DHCP server. Everything works great except that no device in 192.168.63.0/24 is accessible from outside (Internet). We forwarded all ports that we needed from TP-LINK to RV325, but looks like RV325 is not forwarding any ports to other IPs (192.168.63.2 for example)

For this example, we did a PAT the TCP port 3000 to 192.168.63.2 81 and ran a nmap scan from an external machine:

Nmap scan report for XXXXXXX (XXXXXXXXX)
Host is up (0.22s latency).
PORT STATE SERVICE
3000/tcp closed ppp

TP-Link is certainly not the problem since if we enable PPTP in RV325, it will show the 1723/tcp open

Here is our PAT settings:

We tried to set firewall permissive access rules or even disable the firewall but to no avail.

Running RV325 on latest firmware, can ping 192.168.63.2 just fine. We just did a factory reset.

Can anyone shed a light?

Firmware Version:

v1.4.2.17 (2017-10-30, 15:50:18)

[RobertBoudrie6337]

I think my problem had to do with my ISP blocking ports they claim not
to block.  As soon as I forwarded from Port 5000 to my sub-1024 well
known port it all started working.   There is an excellent chance this
was not a problem with the Cisco.

[randrade86]

My unit was faulty. I bought an used Fortigate router and it worked flawlessly. We retired our Cisco RV325.