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Hi there, From what you are describing the first thought that came to me is a wrongly implemented relative URL. What I would do in this case: run a full crawl for the website with screaming frog (you will need a paid version) and make a bulk export for 404 inlinks via: Bulk Export -> Response Codes -> Client error (4xx) Inlinks. I would use that list to find a pattern in the anchor texts used to generate these kind of URLs. When you have found a pattern you can go digg into the source code of the pages where the links come from. If you don't have a Screaming frog license, send me a PM with the website and I will make a quick crawl for you. Istvan