TunnelBroker Hook not working but data is correct

I´ve got this error:
Get "https://ipv4.tunnelbroker.net/nic/update?hostname=<correct hostname>&myip=<my current IPv4>": context deadline exceeded (Client.Timeout exceeded while awaiting headers)
The state is enabled and the last execution was 2020-08-02 12:26:25 UTC.
Last result: -

Can you trigger a change of your IP address? There is no mechanism to retry a failed hook execution. The current timeout is 20 seconds.

I wonder why we used the https://ipv4.tunnelbroker.net/ … I changed it to https://tunnelbroker.net/

I´ve already triggered a change of my IP address. Still the same problem.

The last exection of your hook at 2020-08-25 19:29:23 succeeded. Please let me know when this happens again.