Replication using GTID with slave connected to a slave reconnects to the master (no replies)

I have this problem using GTID based replication:

Master is written to;
Slave1 replicates from Master and gets additonal data.
Slave2 is connected to Slave1.

After a restart of mysql on Slave2, this connect directly to Master. I cannot find any way to enforce Slave2 to connect to Slave1.