1. Post your SNR and Attenuation values. Table for speed less than 8 Mbps If your values are bad, ask the line man to give a clean line. Make sure there are no joints or non insulated parts. 2. Make sure all connections come after splitter. Follow this diagram Bypass the splitter, connect the line directly to the modem and check. 3. Check if splitter or ethernet cable is faulty. Use a spare one and check. 4. If possible get a friend's modem and check. That will confirm if modem is faulty or not. 5. Do you get power reset ? If yes, check modem's power adpater and make sure it is functioning well. 6. Try GDMT mode in modem and check.