RouteOS 7.19.1, SSTP has become unstable.

Something broke in 7.19.1. My sstp started crashing periodically. The only thing that helps is reducing the keepalive timeout. Older devices with router os 7.18.2 work stably.

Send a supout report to MT on their support page…

We have seen the same instability running 2 CCR2116-12G-4S+ routers with ROS 7.19.1 in a data center environment. Prior to updating our routers with ROS 7.19.1 we had run for 6+ months with ROS 7.16.1 without any issues.
In our environment the CCR2116 devices (one primary and the other is backup with VRRP between them) run the SSTP-SERVER and 2800+ SSTP VPN connections from about ~2500 951G-2Hnd and ~300 hAP ax^3 devices run the Mikrotik SSTP-client. Since we updated on May 28 (~7 days ago) we have experienced 3 failures where most or all of the SSTP VPN connections have been terminated. A script in the primary router monitoring the number of active VPNs automatically triggers a VRRP failover when we lose 500 or more VPNs from the Mikrotik devices in a short time. During that time interval (2-3 minutes) during which the VPNs terminated there have been no network issues.
After the failover in which the backup router takes over and the primary reboots itself, only about 80-90% of the remote devices reconnect to the server. The remaining 10-20% of the devices indicate the sstp-client connections are ‘terminating’ and will require either a disconnect and reconnect of the ether1 interface (used by the VPN connection) or a power cycle to again reconnect to the data center routers running the SSTP server . After this action is completed (which unfortunately requires an on-site visit to accomplish) the VPN sstp clients on the remote devices immediately reconnect its VPN to the data center. While running ROS 7.16.1, on the few occasions we had a planned outage, all of the SSTP client devices successfully reconnected to the data center without manual intervention.
Overnight tonight we plan to downgrade to ROS 7.16.1

on a RB5009 with Firmware 7.18.1 or 7.19.4 SSTP was unstable with Windows Client.
Disable AES256-GCM-SHA384 on SSTP Server helps