If new screws are not threading properly into previously used screw holes in an interior door, there are a few potential solutions you can try:
Use larger screws: If the previous screw holes have become worn or enlarged, you can try using slightly larger screws with a slightly larger diameter. The larger screws may find new purchase and hold more securely.
Use longer screws: If the previous screws were relatively short, you can try using longer screws. The longer screws may be able to grip into fresh wood within the door frame and provide a better hold.
Fill the old screw holes: If the previous screw holes are too worn or damaged, you can fill them with a suitable material such as wooden dowels, toothpicks, or wood filler. Insert the filler material into the hole and trim it flush with the surface. Then, you can drill new pilot holes into the filled area and screw into the fresh wood.
Use wall anchors or plugs: If the previous screw holes are beyond repair, you can consider using wall anchors or plugs designed for the specific material of the door frame. These devices can provide a secure hold even in softer or less stable surfaces.
Before attempting any of these solutions, it's a good idea to remove any debris or obstructions from the old screw holes and ensure that the new screws are appropriate in size and length for the job. If you're unsure or uncomfortable with DIY solutions, it's advisable to consult a professional carpenter or handyman who can assess the situation and provide appropriate guidance.