IDX12709: CanReadToken() returned false. JWT is not well formed: '[PII is hidden]'.
The token needs to be in JWS or JWE Compact Serialization Format.
(JWS): 'EncodedHeader.EndcodedPayload.EncodedSignature'.
(JWE): 'EncodedProtectedHeader.EncodedEncryptedKey.EncodedInitializationVector.EncodedCiphertext.EncodedAuthenticationTag'.

public static Boolean ValidateToken(string jwtToken,  string key)
    {
        var securityKey = new SymmetricSecurityKey(Convert.FromBase64String(key));
        var validationParameters = new TokenValidationParameters()
        {
            ValidateIssuerSigningKey = true,
            IssuerSigningKey = securityKey
        };
        SecurityToken validatedToken;
        var claimPrincipal = new JwtSecurityTokenHandler().ValidateToken(jwtToken, validationParameters, out validatedToken);

        return validatedToken.ValidFrom <= DateTime.Now;
    }