I try to validate an access token, which I get from Azure. I created the token the following way: 1. I did an Azure AD App Registration for our application. 2. Created a Search Bot and added the app registration to the bot. 3. I tested the connection in the bot successfull an got an Access Token ![102398-createaccesstoken.png][1] In our c# application we try to validate the Token with JWTSecurityTokenHandler, but die signature is invalid: Microsoft.IdentityModel.Tokens.SecurityTokenInvalidSignatureException HResult=0x80131500 Message=IDX10511: Signature validation failed. Keys tried: 'System.Text.StringBuilder'. kid: 'System.String'. Exceptions caught: 'System.Text.StringBuilder'. token: 'System.IdentityModel.Tokens.Jwt.JwtSecurityToken'. Source=TokenTestApp StackTrace: at TokenTestApp.Program.ValidateTokenInternal(String token, String issuer, String validAudience, String wellKnownUrl, CancellationToken ct) in C:\Users\ttt\Source\Repos\TokenTestApp\TokenTestApp\Program.cs:line 109 at TokenTestApp.Program.Main(String[] args) in C:\Users\ttt\Source\Repos\TokenTestApp\TokenTestApp\Program.cs:line 23 The only way around this was to deactivate the signature validation by using the SignatureValidator delegate in the TokenValidationParameters class – which is obviously a bad idee. Is there a way to validate these tokens with the JWTSecurityTokenHandler? Thanks for your help! [1]: /answers/storage/attachments/102398-createaccesstoken.png