problem:
Client does not support authentication protocol requested by server;upgrading MYSQL Client
Solution:
1. Open the cmd window, enter the bin directory of the mysql installation directory, enter: mysql -u root -p to connect to the database, then enter the password, and press Enter
2. Enter the following commands respectively:
# 修改加密规则
（1）ALTER USER 'root'@'localhost' IDENTIFIED BY 'password' PASSWORD EXPIRE NEVER;
# 更新一下用户的密码
（2）ALTER USER 'root'@'localhost' IDENTIFIED WITH mysql_native_password BY 'password';
# 刷新权限
（3）FLUSH PRIVILEGES; 
3. Reopen Navicat, enter the account and password, and click the "connection test" button. At this time, it will appear: connection is successful
4. Click "OK" to successfully connect to the database
