Trying to connect to a Trados GroupShare 2017/2020 server and open a server-based Translation Memory in  Trados Studio 2021 using the Windows Authentication method the following error message is displayed:

Response status code does not indicate success: 400 (Bad Request).



While on the Trados GroupShare application server, the ApplicationService.log log file shows the following error message:
 

2022-01-27 08:55:04.410#Rest Api#GET http://localhost:41234/licenseserver/api/license/TMServer.CALs
2022-01-27 08:55:04.504#Hosting.WindowsServiceHost#Microsoft.EntityFrameworkCore.SqlServer, Version=1.1.3.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.598#Hosting.WindowsServiceHost#Microsoft.EntityFrameworkCore.Relational, Version=1.1.3.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.613#Hosting.WindowsServiceHost#System.ComponentModel, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.660#Hosting.WindowsServiceHost#Microsoft.Extensions.DependencyInjection, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.660#Hosting.WindowsServiceHost#System.Collections, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.691#Hosting.WindowsServiceHost#Microsoft.Extensions.Logging, Version=1.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.691#Hosting.WindowsServiceHost#System.Linq, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.723#Hosting.WindowsServiceHost#Microsoft.Extensions.Caching.Memory, Version=1.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.754#Hosting.WindowsServiceHost#Microsoft.Extensions.Options, Version=1.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.770#Hosting.WindowsServiceHost#Microsoft.Extensions.Caching.Abstractions, Version=1.1.1.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:04.816#Hosting.WindowsServiceHost#System.Diagnostics.DiagnosticSource, Version=4.0.1.1, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51
2022-01-27 08:55:04.832#Hosting.WindowsServiceHost#System.Collections.Concurrent, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.832#Hosting.WindowsServiceHost#System.Reflection, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.832#Hosting.WindowsServiceHost#System.Threading, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.832#Hosting.WindowsServiceHost#System.Runtime.Extensions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.848#Hosting.WindowsServiceHost#System.Threading.Tasks, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.895#Hosting.WindowsServiceHost#System.Linq.Expressions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:04.941#Hosting.WindowsServiceHost#Microsoft.Extensions.Primitives, Version=1.1.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60
2022-01-27 08:55:05.113#Hosting.WindowsServiceHost#System.Collections.Immutable, Version=1.2.3.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:05.113#Hosting.WindowsServiceHost#netstandard, Version=2.0.0.0, Culture=neutral, PublicKeyToken=cc7b13ffcd2ddd51
2022-01-27 08:55:05.363#Hosting.WindowsServiceHost#System.Diagnostics.Tracing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a
2022-01-27 08:55:11.348#SecurityHandler.OAuthTokenHandler#Setting SetCurrentThreadUniqueIdentity to Domain\username
2022-01-27 08:55:11.348#Rest Api#GET http://spysdl03:41234/api/management/v2/backgroundtasks?_dc=1643270111195&page=1&start=0&limit=5&sort=%5B
{"property"%3A"CreatedAt"%2C"direction"%3A"DESC"}%5D&filter={"Status"%3A16%2C"Type"%3A13}
2022-01-27 08:55:11.426#Management.RestApi#TMServiceProxy: requesting TM-Service background tasks, GET http://localhost:41235/api/tmservice/tasks?$count=
true&$top=5&$skip=0&$filter=(Type eq 'TmService.Export') and (Status eq 
Sdl.TMService.Data.BackgroundTaskStatus'Done')&$orderby=CreatedAt desc
2022-01-27 08:55:11.566#SecurityHandler.OAuthTokenHandler#Setting SetCurrentThreadUniqueIdentity to Domain\username

 

There are currently three workarounds for this issue:

Workaround A - Authenticate with a different user

1. While in Trados Studio go to the File-Setup-Servers menu
2. Fill in the server details and port, click Next
3. In the Authentication screen select Windows Authentication as the Login Provider
4. Mark the Authenticate with a different user box
5. Fill in the domain\username and password details

Workaround B - GroupShare Authentication

While having a GroupShare user already created in the Trados GroupShare WebUI ( fSDL User type), please do the following:

1. While in Trados Studio go to the File-Setup-Servers menu
2. Fill in the server details and port, click Next
3. In the Authentication screen select GroupShare Authentication as the Login Provider
4. Fill in the domain\username and password details

Workaround C - Remove your domain username if it is part of many and unnecessary Active Directory groups.

 

The Windows Authentication method was not working via Kerberos for some users. Kerberos is the network security protocol used by Trados Studio to authenticate service requests from/to Trados GroupShare.
In some cases, the domain user, may be part of many Active Directory groups, this causing the token size to grow considerably. The sent token will be truncated when it reaches IIS. Because of this, a 400 error message (Bad request) is received.
 

You may also be interested in reading the following articles:

What is the Kerberos network security protocol and how it works?
How do I configure the Windows Authentication for SDL Trados GroupShare 2017 (or higher)?
Windows Authentication fails when working with GroupShare 2017 translation memories: There was a connection protocol error. Please check that you have entered the correct port number and other settings.
How to find the log files for Trados GroupShare, Trados Studio or MultiTerm Desktop.
SDL Trados GroupShare 2017 - Installation Guide and Release Notes.
SDL Trados GroupShare 2020 - Installation Guide and Release Notes.