SoftEther (SSTP) + Mikrotik why does the connection break even under minimal load?

Question

Mikrotik

Good afternoon,
there is a SoftEther server with SSTP raised on it, connecting to it from a standard Windows 8 client, everything works fine. There is a Mikrotik with an SSTP client configured on it in the direction of Softether connection, there are clients pinged in the same server, moreover, you can get in the SSTP tunnel from the client to the router (and the connection is stable)
But it’s worth giving a load (after turning the routes towards SoftEther), for example, just from the router with the fetch url=****" mode=http command, download the file, then the connection breaks, without giving a load, the connection can be at least a whole day without breaking the connection.
There is nothing really clear in the logs, Mikrotik reports that the remote side has disconnected , there is also silence on the SoftEther side.
I already wrote to the Mikrotik support, they agreed that put Mikrotik instead of Softether :)
Who faced this, tell me where to dig?

Answer 1

I racked my brains for about two weeks, spat raised Mikrotik + Mikrotik = excellent SSTP.
Note:
With the latest Mikrotik firmware (6.32) softether and Mikrotik don't rise at all :)

Answer 2

I'm afraid that the diversity of network hardware at the ends of tunnels often plays a negative role. It is necessary to sniff the traffic, look at what moment the protocol mismatch occurs. And send it to Mikrotik support or SoftEther, depending on whose side the RFC is violated =)