VPS Hardware Host changed IP Address – DNS / MySQL Errors

Hi,
Our VPS hardware host changed our slave DNS server IP address with literally two minuets notice last night!!
KEY
OLD IP ADDRESS = old.old.old.old
NEW IP ADDRESS = new.new.new.new
Debugging the slave server I now get the following errors: -

I took the following steps to change the IP Address
1/ Changed /etc/hosts old slave IP address to the new IP address on MASTER SERVER
2/ Changed /etc/hosts old slave IP address to the new IP address on SLAVE SERVER
3/ on MASTER SERVER I made changes to the DB
mysql -u root -p
Enter password: MASTER-SERVER-PASSWORD

Code:

REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'root'@'slave.DOMAIN.com';
REVOKE ALL PRIVILEGES, GRANT OPTION FROM 'root'@'old.old.old.old';
DROP USER 'root'@'old.old.old.old';
DROP USER 'root'@'slave.DOMAIN.com';
FLUSH PRIVILEGES;

CREATE USER 'root'@'new.new.new.new' IDENTIFIED BY 'MASTER-SERVER-PASSWORD';
GRANT ALL PRIVILEGES ON * . * TO 'root'@'new.new.new.new' IDENTIFIED BY 'MASTER-SERVER-PASSWORD' WITH GRANT OPTION MAX_QUERIES_PER_HOUR 0 MAX_CONNECTIONS_PER_HOUR 0 MAX_UPDATES_PER_HOUR 0 MAX_USER_CONNECTIONS 0 ;
CREATE USER 'root'@'slave.DOMAIN.com' IDENTIFIED BY 'MASTER-SERVER-PASSWORD';
GRANT ALL PRIVILEGES ON * . * TO 'root'@'slave.DOMAIN.com' IDENTIFIED BY 'MASTER-SERVER-PASSWORD' WITH GRANT OPTION MAX_QUERIES_PER_HOUR 0 MAX_CONNECTIONS_PER_HOUR 0 MAX_UPDATES_PER_HOUR 0 MAX_USER_CONNECTIONS 0 ;
FLUSH PRIVILEGES;
EXIT;

4/ ISPConfig Admin Panel
Admin > System > Server Config > slave.DOMAIN.com
changed IP Address from old.old.old.old TO new.new.new.new
5/ Slave Server tried to login to Master DB using: -

Code:

mysql -h master.DOMAIN.com -u ispcsrv2 -p
Password: MASTER-SERVER-PASSWORD

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Have I missed something?
As always many thanks in advance for your kind help
Kind regards and Seasons Greetings to all
HTA

 

Hi Till,
Brilliant as always.
All sorted now thanks to your kind help.
With kind regards as always
HTA