Dependency Injection Involving Struct types

I have a class as shown below,

public class AccessToken : IAuthToken
{
    /// <summary>
    /// Initializes a new instance of the <see cref="AccessToken"/> class.
    /// </summary>
    /// <param name="token">The token.</param>
    /// <param name="validTo">The valid to.</param>
    public AccessToken(string token, DateTimeOffset validTo)
    {
        ValidTo = validTo;
        Token = token;
    }

    ///<inheritdoc />
    public DateTimeOffset ValidTo { get; private set; }

    /// <summary>
    /// Gets the RAW Jwt token value. 
    /// This value is encoded and represents the Jwt token.
    /// </summary>
    /// <value>
    /// The token.
    /// </value>
    public string Token { get; private set; }
}

The DI code goes like this,

return services
    .AddTransient<IAuthToken, AccessToken>()
    .AddTransient<IAuthTokenService, AuthTokenService>()
    .AddSingleton<IIdentityDiscovery, IdentityDiscovery>()
    .AddTransient<IIdentityTokenClient, IdentityTokenClient>()
    .AddTransient<IDiscoveryClientRetryPolicy, DiscoveryClientRetryPolicy>()
    .AddTransient<ITokenClientRetryPolicy, TokenClientRetryPolicy>()
    .AddSingleton<IRetryPolicyOptions>(provider => retryOptions);

The whole thing is packaged as a nuget. When this DI code is called from .net461 it works fine but when used in net core 6, I get an error stating it's unable to resolve type string and DateTimeOffset. I tried to inject a dummy string and the string error vanished but the struct DateTimeOffset persisted. Does .net6 interpret this DI in a different way?