Hello,
Thank you for reaching out,
It sounds like you're dealing with a PPTP VPN issue where you used to be able to connect without problems but now cannot. Since the router settings are unchanged and Windows Defender firewall was ruled out, we should explore a few other potential causes:
1. Check VPN Server Settings on Windows 10
Ensure that the VPN server is still enabled on your Windows 10 host. Go to Control Panel > Network and Sharing Center > Change adapter settings, then right-click on your VPN connection (or Incoming Connections) and select Properties.
Under the Networking tab, make sure that Allow callers to access my local network is checked.
2. Check for Windows Update or Changes
Even though you weren't vigilant, Windows 10 updates can sometimes cause changes to VPN services or networking settings. Try checking the system logs for any recent updates that may have affected the VPN functionality:
Go to Settings > Update & Security > Windows Update and see if there are any recent updates, especially security-related ones.
3. Enable PPTP in Router (if applicable)
Some routers have specific firewall or NAT settings that can block PPTP traffic (TCP port 1723 and GRE protocol 47). Ensure that your router has these ports forwarded correctly and that PPTP passthrough is enabled.
4. Check for Network Layer Issues
Network Isolation: Ensure that both devices (remote and host) are on the correct network (you mentioned a router, but VPN traffic may be getting blocked by local network rules).
VPN Server Configuration: Verify that the PPTP VPN server on your Windows 10 machine is properly configured and the IP range for VPN connections hasn't changed. You can reset the VPN settings by disabling and re-enabling the VPN server in Network Connections.
5. Recheck Firewall and Security Software
You mentioned turning off Windows Defender, but if you have any third-party security software installed (such as antivirus or a third-party firewall), it might still be blocking the connection. Disable or temporarily uninstall any additional security software to test.
6. Check for VPN Client Software Updates
Make sure that the VPN client software on both the Android device and the Windows 10 laptop is up to date. Sometimes, updates can address compatibility issues with Windows 10’s networking features.
7. Test Using Other VPN Protocols (as a workaround)
If you continue to have issues with PPTP, you could temporarily try using L2TP/IPsec or OpenVPN (which are generally more secure) to check if the problem lies with the PPTP protocol specifically.