Repair slave in MySQL GTID replication, after fatal error 1236 (master has purged binary logs)

For repairing a broken slave after fatal error 1236.

Last_IO_Error: Got fatal error 1236 from master when reading data from binary log: 'The slave is connecting using CHANGE MASTER TO MASTER_AUTO_POSITION = 1, but the master has purged binary logs containing GTIDs that the slave requires.'

slave# reset master;

slave# source /pathto/dump.sql;

slave# start slave for channel 'mymaster';

slave# show slave status for channel 'mymaster'\G

Here is another useful tutorial, if the problem persists

https://www.percona.com/blog/2013/02/08/how-to-createrestore-a-slave-using-gtid-replication-in-mysql-5-6/