It was:

Wed 19 Nov 04:04:32 2014 | climateprediction.net | Started upload of hadam3p_eu_j6bm_1988_1_008500039_0_13.zip
Wed 19 Nov 04:05:48 2014 |  | Project communication failed: attempting access to reference site
Wed 19 Nov 04:05:48 2014 | climateprediction.net | Temporarily failed upload of hadam3p_eu_j6bm_1988_1_008500039_0_13.zip: connect() failed
Wed 19 Nov 04:05:48 2014 | climateprediction.net | Backing off 05:52:23 on upload of hadam3p_eu_j6bm_1988_1_008500039_0_13.zip
Wed 19 Nov 04:05:49 2014 |  | Internet access OK - project servers may be temporarily down.

(CET timezone)

But right now it is uploading, after I hit "Retry Now" to replicate the error msg.

A recurrence of an old friend:

24/02/2015 07:51:26 | climateprediction.net | Started upload of hadcm3n_xcqv_1940_40_009152813_2_2.zip
24/02/2015 07:51:48 | climateprediction.net | Temporarily failed upload of hadcm3n_xcqv_1940_40_009152813_2_2.zip: connect() failed
24/02/2015 07:51:48 | climateprediction.net | Backing off 04:01:53 on upload of hadcm3n_xcqv_1940_40_009152813_2_2.zip
24/02/2015 07:51:52 | | Project communication failed: attempting access to reference site
24/02/2015 07:51:53 | | Internet access OK - project servers may be temporarily down.