Failed to check available update data for [X] error

Hello,
I am trying to update my drupal site with drush as usual, but I have a long list of "Failed to check available update data for [MODULENAME] [OK]" errors... (not that I still get an OK ?????)

I did already:

1. run drush rf
2. run drush pm-refresh
3. drush ev "_update_cache_clear()" (that is, truncated the cache_update table)
4. disabled/uninstalled/reinstalled the update module
5. checked https://twitter.com/drupal_infra?lang=en

..any other suggestion ??? :-(