“Access restriction: The type BASE64Encoder is not accessible due to restrict“问题解决

"Access restriction: The type BASE64Encoder is not accessible due to restrict"问题解决

参考文章：

（1）"Access restriction: The type BASE64Encoder is not accessible due to restrict"问题解决

（2）https://www.cnblogs.com/Anidot/p/7753281.html

（3）https://www.codeprj.com/blog/764e411.html