Download and install the latest "Autodesk Licensing Service" update from the official support site. Even for 2015 versions, a newer licensing component can sometimes bridge the communication gap with modern servers.
Modern Windows versions may block 2015 drivers. You can temporarily disable "Driver Signature Enforcement" in the Advanced Startup menu to allow the installer to proceed. autocad lt 2015 download fix
Once the software is running, you may notice "ghosting" lines or slow cursor movement. This is because AutoCAD LT 2015 was not optimized for modern high-resolution (4K) monitors or DirectX 12. Download and install the latest "Autodesk Licensing Service"
Type GRAPHICSCONFIG in the command line and try toggling Hardware Acceleration off. If the performance improves, the issue is a conflict with your modern GPU driver. Type GRAPHICSCONFIG in the command line and try
If the 2015 version is not listed, use the Autodesk Virtual Agent chat. Type "Download AutoCAD LT 2015" to receive a direct link to the installer parts.
Are you getting a (like 1603 or 0xc000007b)? Do you still have your original serial number ? Which version of Windows are you currently using?