Plesk 12 Login error after changing MySql Password -Resolved

1. old-passwords = 1 should be disabled in the /etc/my.cnf file.
2. Obtain the correct Plesk password: cat /etc/psa/.psa.shadow ($AES-128-CBC$33yZTimLYQFax/iFgiQGkQ==$gqGlImLkTalp26cDeS3C9g==)
3. sudo /etc/init.d/mysqld stop
4. sudo mysqld_safe --skip-grant-tables &
5. mysql -u admin
6. update mysql.user set password=PASSWORD("$AES-128-CBC$33yZTimLYQFax/iFgiQGkQ==$gqGlImLkTalp26cDeS3C9g==") where User='admin';
7. flush privileges;
8. sudo /etc/init.d/mysqld stop
9. sudo /etc/init.d/mysqld start

Update the password for Plesk using the ch_admin_passwd utility:

1. /usr/local/psa/bin/admin --show-password
2. export PSA_PASSWORD=Abe3s3
3. /usr/local/psa/admin/bin/ch_admin_passwd