Hi, I'm totally flabbergasted now.
Flickr gallery is running fine on one WordPress (3.0.4, Theme Twenty Ten). On an other installation, same version, same provider, the settings page returns the message:
The Flickr API has returned the following error message.
96: Invalid signature
The values for API key and User ID were copied and pasted from one to the other.
Switching to Twenty Ten doesn't change anything, neither does using a different browser (caching issues having been mentioned somewhere).
Flickr gallery is the only plugin active on the problem-WP.
Any ideas? I'd be grateful for any help...