MySQL: Incorrect binary log format - OFF.000
I have seen your problem before

Problem #1

You have /etc/mysql/conf.d/mycustom.cnf and the log-bin line is not being read

Problem #2

Chances are /etc/mysql/conf.d/my.cnf exists and has the following line

[mysqld]
log-bin=OFF


That's why the binlogs start with a filename of OFF

Some feel log-bin=OFF disables binlogging. The MySQL Documentation on log-bin says the permitted value is a filename. Thus, it is not boolean. Simply removing the line or commenting it out disables binlogging.

Suggestion #1

You may want to start mysqld manually using

service mysql stop
mysqld --defaults-file="/etc/mysql/conf.d/mycustom.cnf"


Suggestion #2

Just change log-bin in /etc/mysql/conf.d/my.cnf

Then service mysql restart

Epilogue

Don't restart mysql just yet. This problem is one the Master.

STEP 01 : Stop all writes to the Master

STEP 02 : Go to the Slave and run STOP SLAVE;

STEP 03 : Restart mysql on the Master

STEP 04 : On the Slave, run this

CHANGE MASTER TO master_log_file='acct-db1-bin.000001',master_log_pos = 4;
START SLAVE;


STEP 05 : Start up all writes to the Master

This should complete your maintenance