IDX10511: Signature validation failed. Keys tried: 'Microsoft.IdentityModel.Tokens.X509SecurityKey

We have an Angular application that is using the capacitor-oauth2 Library to get tokens from our Azure AD and Azure B2C AD. when I have the Token from B2C I can verify it with following Code in my Program.cs and I can call my Controller Function

builder.Services.AddAuthentication(options =>
    {
        options.DefaultAuthenticateScheme = JwtBearerDefaults.AuthenticationScheme;
    })
    .AddJwtBearer("B2C", options =>
    {
        options.Authority = $"https://eisvogel2.b2clogin.com/eisvogel2.onmicrosoft.com/B2C_1_susi/v2.0/";
        options.Audience = $"6fba7d06-5b7a-41bd-8371-6f1ad6f3176c";
    });

But when I get a Token from our internal AD which is coming from MS Graph I can do what I want I always get the following Exception:

for this I'm using the code that the Studio is generating when creating a new Solution with authentication builder.Services.AddAuthentication(JwtBearerDefaults.AuthenticationScheme) .AddMicrosoftIdentityWebApi(builder.Configuration.GetSection("AzureAd")); and changed the Config

I already tried the conclusions from various posts, but nothing really helps

I know there are a lot of similar posts, and I've been searching for 3 days now. It would be nice if someone could nudge me in the right direction.

Remark: I forgot to mention that I built the solution on .NET 6. are there any differences to the predecessors?