Error establishing connection client-server

[qeeon12]

I am triyng to run SoftEthere server on Windows 10. I have completed all steps of the hub configuration. But when i am triyng to connect client via L2TP with built in Windows client i allways get security layer error, i get such error even if I turn hub offline on server. I checked all ports, they are all open and accessible outside (500 and 4500 UDP). Listener configured on TCP ports 443, 992, 1194, 5555. Also i checked user config (login/pass auth) and IPsec shared key. I checked speed connection with built in utilite "Network traffic" between client and server on default port 9821 and it was all ok. Also connection is working well with SoftEthere Client app.
Is there any suggestions what i can check next?

[solo]

viewtopic.php?f=7&t=69614

[qeeon12]

I don't think my provider blocks port i uses, i checked it localy and get this for process "vpnserver_x64.exe":

UDP ports:
0.0.0.0:53
0.0.0.0:500
0.0.0.0:1194
0.0.0.0:4500
0.0.0.0:55450
0.0.0.0:64103
0.0.0.0:64673
127.0.0.1:500
127.0.0.1:1194
127.0.0.1:4500
*server external ip*:500
*server external ip*:1194
*server external ip*:4500

TCP ports:
0.0.0.0:443
0.0.0.0:992
0.0.0.0:1194
0.0.0.0:5555
0.0.0.0:43756
127.0.0.1:5555
*server external ip*:443

I checked ports 500,1194,4500,433 on external ip using online port scaner, they were all accessible from outside.
Also i checked processes that are using ports 500,1194,4500,433 and there was only vpnserver_x64.exe listening for thoes ports. So i don't think there is conflict with services running loclaly and using the same ports.

[solo]

Read again viewtopic.php?f=7&t=69614#p103283

"On SE client disable NAT-T and if you can't connect now to... [*server external ip*:443], your port forwarding is useless because ISP is blocking incoming connections."

[qeeon12]

SE NAT-T was disabled by default, but when i turn it on/off result is the same.

Also i checked with nmap outside connection to ports 433, 500 and 4500, when i turn off service "SEVPNSERVER" port goes offline, and nmap does't get any response, when i turn service "SEVPNSERVER" on it shows on 433 port "tcp filtred nnsp", 500 port "tcp filtered isakmp" and on 4500 "tcp filtered sae-urn".
I am not a guru of network technologies, but i don't understand how ISP block client connections and in the same time ports respond to nmpa query from outside.... and react on turning off/on service "SEVPNSERVER".

[qeeon12]

I get answer from tech support of data center where my server is located, they confirmed that ISP blocks, L2TP and IPsec. So i think they block traffic somehow...