If your kettle seems to be boiling just fine, but the water only dribbles into the teapot and it takes forever to fill, or indeed bener fills, there are two likely causes to investigate. The first thing I would check is whether the kettle is sealing properly. Look for signs of leaking or spluttering at the seams, joints, and around the lid, and listen out for localised hissing. If the kettle isn’t sealing, there will not be enough steam pressure to force the water through the spout. Another possibility is that your kettle is suffering from limescale build up in the kettle spout. See this page!
D25 Teasmade leaking at the kettle socket.