Can't connect to PPTP Server

[555|STi]

Hi guys, I'm here to ask for your help.

I need to connect two machines,

Machine_1 -> 3G broadband router -> Internet -> OPNSense -> Local PPTP Server (Machine_2)

So, I mounted a PPTP Server on my local Ubuntu Server.

My current network is as follows:

LAN: 172.17.10.1/23

172.17.10.1: OPNsense 19.1.4-amd64 / FreeBSD 11.2-RELEASE-p9-HBSD / OpenSSL 1.0.2r 26 Feb 2019
172.17.10.2: Ubuntu Server 16.04 / pptpd server v1.4.0

The rest of the network has some computers, servers and clients.

What I can't achieve, yet, is to connect a pptp client from outside the LAN. Inside the LAN it works flawlessly, I can connect from my mobile phone, and my laptop with Win7x64. So, I assume that the pptp server is correctly configured.

But when I try to connect from outside the LAN, the local pptp server detects the connection, and shortly after it throws an Error 619. I can see the incoming connection from the Webmin Panel. It even shows my 3g IP address. So, it does see me, but the connection can't be fully established.

My current settings are as follows. And I would love you to tell me if I'm making a mistake.

This is my NAT: Port Forwarding config

WAN     TCP/UDP     *   *   This Firewall   1723 (PPTP)     172.17.10.2     1723 (PPTP)
WAN     GRE         *   *   This Firewall   *               172.17.10.2     *

These are my WAN Rules

IPv4 TCP/UDP    *   *   172.17.10.2     1723 (PPTP)     *       NAT
IPv4 GRE        *   *   172.17.10.2     *               *       NAT

And these, my LAN Rules

IPv4 TCP/UDP    *   *   *   1723 (PPTP)     *           
IPv4 GRE        *   *   *   *               *         

Any help would be really appreciated, thanks in advance. 

[555|STi]

Well, I've been tweaking some settings and testing some configs, and...

Got this log on the pptp server hosted on the same OPNSense.

Mar 15 17:07:28    pptps: [L-1] Link: Shutdown
Mar 15 17:07:28    pptps: [L-1] Link: SHUTDOWN event
Mar 15 17:07:28    pptps: [L-1] LCP: state change Closed --> Initial
Mar 15 17:07:28    pptps: [L-1] LCP: Down event
Mar 15 17:07:28    pptps: [L-1] LCP: state change Stopped --> Closed
Mar 15 17:07:28    pptps: [L-1] LCP: Close event
Mar 15 17:07:28    pptps: [L-1] Link: DOWN event
Mar 15 17:07:28    pptps: [L-1] PPTP call terminated
Mar 15 17:07:28    pptps: [L-1] LCP: LayerFinish
Mar 15 17:07:28    pptps: [L-1] LCP: state change Ack-Sent --> Stopped
Mar 15 17:07:28    pptps: [L-1] LCP: parameter negotiation failed
Mar 15 17:07:28    pptps: [L-1] LCP: not converging
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Reject #10 (Ack-Sent)
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] MAGICNUM 0x6cdae81a
Mar 15 17:07:28    pptps: [L-1] MRU 1500
Mar 15 17:07:28    pptps: [L-1] LCP: SendConfigReq #10
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Reject #9 (Ack-Sent)
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] MAGICNUM 0x6cdae81a
Mar 15 17:07:28    pptps: [L-1] MRU 1500
Mar 15 17:07:28    pptps: [L-1] LCP: SendConfigReq #9
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Reject #8 (Ack-Sent)
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] MAGICNUM 0x6cdae81a
Mar 15 17:07:28    pptps: [L-1] MRU 1500
Mar 15 17:07:28    pptps: [L-1] LCP: SendConfigReq #8
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MD5
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Nak #7 (Ack-Sent)
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] MAGICNUM 0x6cdae81a
Mar 15 17:07:28    pptps: [L-1] MRU 1500
Mar 15 17:07:28    pptps: [L-1] LCP: SendConfigReq #7
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MD5
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Nak #6 (Ack-Sent)
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] MAGICNUM 0x6cdae81a
Mar 15 17:07:28    pptps: [L-1] MRU 1500
Mar 15 17:07:28    pptps: [L-1] LCP: SendConfigReq #6
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MD5
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Nak #5 (Ack-Sent)
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MSOFTv2
Mar 15 17:07:28    pptps: [L-1] MAGICNUM 0x6cdae81a
Mar 15 17:07:28    pptps: [L-1] MRU 1500
Mar 15 17:07:28    pptps: [L-1] LCP: SendConfigReq #5
Mar 15 17:07:28    pptps: [L-1] AUTHPROTO CHAP MD5
Mar 15 17:07:28    pptps: [L-1] LCP: rec'd Configure Nak #4 (Ack-Sent)

Still trying to connect, though.