After restoring a backup mysqldump file from one server to another, I found that my WordPress user passwords were no longer working correctly, despite knowing I was using the correct password. Apparently because WordPress hashes passwords with md5 in the user table, it could be that attempting logon on another server the md5 hash was computing differently.\, The simple fix was to reset passwords in the wp_users table with a new hash, using:
update wp_users set user_pass = md5('NEW_PASSWORD') where user_login = 'USER-TO-UPDATE';
