Troubleshooting SSTP client (dis)connection

I’m using several 951Ui-2HnD devices both in SSTP server and SSTP client mode, everything works fine.
I have also 941-2nD which try to use as SSTP client connecting to 951Ui-2HnD SSTP server.
For some reason 941-2nD does not detect network disconnections and show 0/0 Tx/Rx traffic until I manually disable and re-enable SSTP client interface.
How to troubleshoot this problem? Maybe 941-2nD (hAP lite) device has known issues with SSTP?
All devices running latest stable (6.43.:sunglasses: RouterOS.

check the certificates and the firewall. maybe something’s not right.