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Thanks for your question. It sounds like both of the suppliers that you previously used are using the same manufacturer and you basically got the same or similar product. I can also see from the references that the cartridge represents 2 ranges of cartridges (CE505X and the CF280X). These go in very different printers which could be why the shape isn't correct for your machine.
We don't list ours against both machines / models so our cartridges are only manufactured for your machine. For that reason I don't think you'll have the same issue. However, I'll ask one of the team to check with the manufacturer and come back to you asap.
Here is the product that we sell for the LaserJet Pro 400 M401dne https://www.tonergiant.co.uk/product/Compatible-HP-80X-High-Capacity-Black-Toner-Cartridge-RECF280X-19553/