Client does not support authentication protocol requested by server; conside 新旧版本密码算法不同引起的错误，只需要设置下密码方式为 mysql_native_password 就可。还是 navicat 做的好，新旧密码都支持。
操作一波
mysql -u root -p
xxxx
use mysql;
show tables;
# 查看已经有的用户
select user, host from user;
# 重新设置下密码，并使之生效
# 之前是 'xxx'@'%' IDENTIFIED BY 'xxxxxx'
'xxx'@'%' IDENTIFIED WITH mysql_native_password BY 'xxxxxx'
flush privileges;