BouncyCastle AsymmetricKeyParameter inaccessible due to its protection level

Question

I have the following class

public class BouncyCastle
{
private AsymmetricKeyParameter asymmetricKeyParameter;
public bool CleanKey(string fullKey, string jwtToken)
{
    try
    {
    var rs256Token = fullKey.Replace("-----BEGIN PUBLIC KEY-----", "");
    rs256Token = rs256Token.Replace("-----END PUBLIC KEY-----", "");
    rs256Token = rs256Token.Replace("\n", "");

    Validate(jwtToken, rs256Token);
    return true;
    }
    catch (Exception e)
    {
    return false;
    }
}

public void Validate(string token, string key)
{
    var keyBytes = Convert.FromBase64String(key); // your key here

    this.asymmetricKeyParameter = PublicKeyFactory.CreateKey(keyBytes);
    RsaKeyParameters rsaKeyParameters = (RsaKeyParameters)asymmetricKeyParameter;
    RSAParameters rsaParameters = new RSAParameters
    {
    Modulus = rsaKeyParameters.Modulus.ToByteArrayUnsigned(),
    Exponent = rsaKeyParameters.Exponent.ToByteArrayUnsigned()
    };
    using (RSACryptoServiceProvider rsa = new RSACryptoServiceProvider())
    {
    rsa.ImportParameters(rsaParameters);
    var validationParameters = new TokenValidationParameters()
    {
        RequireExpirationTime = false,
        RequireSignedTokens = true,
        ValidateAudience = false,
        ValidateIssuer = false,
        IssuerSigningKey = new RsaSecurityKey(rsa)
    };
    var handler = new JwtSecurityTokenHandler();
    var result = handler.ValidateToken(token, validationParameters, out var validatedToken);
    }
}
}

When I compile it locally in visual studio it compile. When I try to build it in an Azure pipeline I get the error

 error CS0122: 'AsymmetricKeyParameter' is inaccessible due to its protection level 

There seems very little of any documentation to go with it. Can anyone help?