https://bugs.kde.org/show_bug.cgi?id=527581
--- Comment #6 from [email protected] --- After investigate I respond to myself : "Why is Mozilla/5.0 banned by Flickr?" Nobody can answer on Flickr's behalf (it's a server-side configuration choice), but the most likely explanation is: 1. A bare Mozilla/5.0 is a bot fingerprint, not a browser's. No real browser ever sends such a short User-Agent: actual browsers send complete strings like Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 ... Chrome/155.0.0.0 Safari/537.36. A User-Agent reduced to just Mozilla/5.0 is the typical signature of a script lazily pretending to be a browser — one of the most common markers used by scrapers and automation tools. Anti-bot systems (WAFs like Cloudflare/Akamai) therefore filter it out as a priority. 2. It's Qt's default User-Agent. QNetworkAccessManager sends Mozilla/5.0 when the application doesn't set one — exactly digiKam's case. Flickr most likely deployed a filtering rule on www.flickr.com/services/rest/ on October 22, 2026 that blocks generic/incomplete User-Agents, which instantly broke all unconfigured Qt clients (hence the two KDE bugs, 527578 and 527581, reported the same day, with the latter absorbing the former as a duplicate). 3. Why a 502 instead of a 403? A blocking rule applied at a gateway/proxy level often manifests as a "Bad Gateway" rather than a clean error code, consistent with filtering happening upstream of the REST service. Practical conclusion for the bug: The fix on digiKam's side is simple and legitimate: set an explicit, informative User-Agent, e.g. digiKam/9.1.0 (https://www.digikam.org), on the Flickr module's requests (Robert's curl test with -A "digiKam" already confirms it works). It's good API practice anyway: providers ask for an identifiable User-Agent so they can distinguish applications, measure their traffic, and reach out if problems arise. A developer could also report the change to Flickr (SmugMug) via their API forum, but the digiKam-side fix is still needed for already-shipped versions. Best regards Gilles Caulier -- You are receiving this mail because: You are watching all bug changes.
