It seems that I may have inadvertently loaded the password validation plugin in MySQL 5.7. This plugin seems to force all passwords to comply to certain rules.
I would l
Uninstall:
mysql> uninstall plugin validate_password;
An uninstalled plugin is not displayed by show plugins;
Install:
mysql> install plugin validate_password SONAME 'validate_password.so';
Disabled by configuration:
[mysqld]
validate_password = OFF
A plugin can be disabled by configuration only if installed.