Repair slave in MySQL GTID replication

Run these commands on MySQL shell, to find "where" replication failed and was broken.

Stop the slave.
SET GTID_NEXT="AUTOMATIC";
stop slave;

Find the point where replication broke.
show slave status\G;

Now find "Executed_Gtid_Set". Example value:
Executed_Gtid_Set: 44d966cc-d84d-11e8-be8d-20677cd3f384:1-2872

Increase of one step to 2873
SET GTID_NEXT="44d966cc-d84d-11e8-be8d-20677cd3f384:2873";

Now start the slave.
start slave;
show slave status\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/

Continue the loop until no error occurs. Enjoy