[HELP] MHP3 Lobbie Problem

[Aurora866]

First of all, I don't know if it's right to write here, but I'm writing because it's not solved.

If I access a room where no one is there first, it works without any problems.
(I can see people and play without problems.)
But when I access the lobby where someone is accessing, I can check the connection through the website and chat, but I can't see anyone.

Please give me a solution.

and I'm sorry that I'm not good at English.

(A problem has occurred since the router was changed, but it is not a router problem.(Asus router))
(For your information, I checked this problem accurately with my friend.)
(It was confirmed that the port was open.)

using version : ppsspp 1.11.3
using iso : Monster hunter 3RD (MHP3)
connect server : myneighborsushicat(dawn) / socom.cc
ppsspp setting :
- Software skinning Unchecked
- Fast Memory Unchecked
- Enable networking/WLAN checked
- (There is no problem with other settings.)
another setting :
- Exception and release of all firewalls
- Port forwarding (27312, 10000, 20001~20004)

The way i tried it :
- DMZ (failed)
- Another version of ppsspp 1.11.2, 1.9.3 (failed)
- Run Windows 7, 8 compatible mode (failed)
- Initialize and reset the router (failed)