MySQL replication on slave server Broken/Stopped without error
Slave_SQL_Running_State: Reading event... 

Suggests that it's working on a large event. If you have MIXED or Row based binary logging and have changed a large amount of data on the master you might end up with a large event or series of large events. Use the mysqlbinlog tool to see what's going on with your relaylog. The master might show a concentration of binary logs over a small period of time (on the filesystem)