OK, I have last beta version 64bit v.15.7 build 3123. Certificat (both) was generated by PUTTYgen, but results are the same as yesterday

I have tested both "Do not verify key file" checked and unchecked.
I have tested two certificates (first without password, second with password) - both in WinSCP SFTP client work flawlessly but in Multi Commander not :-(
There are log files in attachment - two from Multi Commnader (for both certificates) and one from WinSCP client for comparision.
2025-12-10 18:59:23 Windows Linebreak are used for text file transfers
2025-12-10 18:59:23 Connecting to sftp.______.cz:1222
2025-12-10 18:59:23 Connected
2025-12-10 18:59:24 Key exchange method : diffie-hellman-group-exchange-sha256
2025-12-10 18:59:24 Host key method : rsa-sha2-512
2025-12-10 18:59:24 Encryption method (both directions) : aes256-ctr
2025-12-10 18:59:24 MAC (message authentication code) method (both directions) : hmac-sha2-256
2025-12-10 18:59:24 Compression method (both directions) : none
2025-12-10 18:59:24 Fingerprint : 3E 0D 34 8A 0F 28 BD 24 8A FA F1 4E E3 03 18 F4
2025-12-10 18:59:24 Failed - Session not connected
2025-12-10 18:59:24 Disconnecting...
2025-12-10 18:59:24 Closing Session...
2025-12-10 18:59:25 Session closed