Hi So i did update the firmware to the new rev.6.46.1 and since then, i got problem to connect to vpn from the Synology Nas. Only from the nas and nothing else was change. I do have a port open in the filter rule as : accept/input tcp 1194, same as since 6month and working fine. This port i used from other pc in the network to connect with openvpn outside server without issues. But somehow i don't know why, only the Nas is blocked and cannot connect to any server.

I try to see if there's some traffic into the firewall - connections pane, but it's quite only udp and not some tcp i see as port 34120, 42478, 47400.., but i do see some : syn sent in TCP state, when i click connect and the nas try to..

So if someone might have some light.. Thanks in advance

Just to follow up, i had enable the : service port : pptp in the firewall / service port tab. and as soon i click all connect fine.
Strange that i had to open it. Perhaps the new firmware block some incoming port by default. I've try before to just put a new rules: tcp accept port 1721 for the pptp.. but of course it doesn't work.

There was some change recently, related to handling of GRE, which is part of PPTP. I didn't follow it closely, but I think it was something like GRE being erroneously allowed before, even when it shouldn't be. And there were complaint from people who relied on this mistake and their PPTP VPNs broke.