Time Sync Sample doesn't work. Not time update from TTN

[MichaelJumble]

Just tried out the example arduino-lmic/examples/ttn-otaa-network-time
that should retrieve the time sync. But after successfully join
I get:

...
Packet queued
18636889: EV_TXCOMPLETE (includes waiting for RX windows)
18702408: EV_TXSTART
19082091: EV_TXCOMPLETE (includes waiting for RX windows)
USER CALLBACK: Not a success
22832109: EV_TXSTART
Packet queued
23151563: EV_TXCOMPLETE (includes waiting for RX windows)
23217081: EV_TXSTART
23596765: EV_TXCOMPLETE (includes waiting for RX windows)
USER CALLBACK: Not a success
27346783: EV_TXSTART
...

Is this example outdated and did not work any longer ?