MsRdpEx session connection failed with authentication error

**Environment:**
1. sspi-rs: master - c016e18863
2. MsRdpEx: v2026.01.12.0 - da020e1 (https://github.com/Devolutions/MsRdpEx/releases)
3. Windows Server: Edition: Windows Server 2025 Standard Evaluation, Version: 24H2, OS build: 26100.32370, Experience: Windows Feature Experience Pack 1000.26100.275.0 [VM]
4. RDP Server: Edition: Windows 11 Pro, Version: 25H2, OS build: 26200.7840, Experience: Windows Feature Experience Pack 1000.26100.291.0 [VM]
5. RDP Client: Edition: Windows 11 Pro, Version: 25H2, OS build: 26200.7840, Experience: Windows Feature Experience Pack 1000.26100.291.0 [VM]

**Preconditions:**
1. Windows Server 2025 [VM] is configured and launched:
- set up and configure Active Directory
- set up and configure DNS server
- create a user for the domain-joined machine

2. RDP server [VM] is configured and launched:
- join Windows 11 to our domain
- enable Remote Desktop
- grant users access via RDP
- modify hosts file

3. RDP Client [VM] is configured and launched:
- modify hosts file
- install MsRdpEx
- set up environment variables:
SSPI_KDC_URL -
SSPI_LOG_LEVEL - trace
SSPI_LOG_PATH -
MSRDPEX_CREDSSP_DLL -
MSRDPEX_LOG_ENABLED - 1
MSRDPEX_LOG_FILE_PATH
MSRDPEX_LOG_LEVEL - TRACE

**Steps:**
1. Open MsRdpEx app
2. Enter valid destination address (for example: TST-RDPS-NM.negomod.lab.test)
3. Enter valid username (for example: joe-moon)
4. Enter valid password
5. Click Connect button

**Actual Result:** MsRdpEx session connection failed with authentication error, see log in attach: sspi-negomod.log, msrdpex.logs.txt, msrdpex-authentication-error.png

[sspi-negomod.log](https://github.com/user-attachments/files/25514386/sspi-negomod.log)
[msrdpex.logs.txt](https://github.com/user-attachments/files/25514387/msrdpex.logs.txt)

**Expected Result:** MsRdpEx connection should be established successfully. The user should be granted access to the system, and the system should proceed to the user's desktop. You can see the remote screen.

**NOTE:**
1. Issue also reproduced with FQDN username format, for example: joe-moon@negomod.lab.test
2. Issue not reproduced with FreeRDP client, checked with FreeRDP (master - 934a486)