longview installation problems

I have two nodes, one where longview works perfect. On the other node it won't report any data. Both nodes are running Ubuntu.

Tests I have done from the node that won't work:

Network connections works. Tested telnet to port 443 on longview.linode.com and the three way handshake was completed.

Started longview in debug mode, and got this error in /var/log/linode/longview.log (the key is anonymised)

08/28 09:38:12 INFO Longview[24098] - 400 Bad Request API key: XXXXXXXX-DEXX-XXXX-XXFE3XXXCEDXXXXX is made up, rejecting payload!
08/28 09:38:12 INFO Longview[24098] - API key: XXXXXXXX-DEXX-XXXX-XXFE3XXXCEDXXXXX is made up, rejecting payload!

I have deleted the node from longview, and reinstalled. Have verified the key from longview in /etc/linode/longview.key - still the same problem, with the same error in the debug log.

And here I'm stuck. Any suggestion on what to check or do, is very welcome. :)

Cheers.