20 August 2018
Try deleting the file ANSYSLI_DEMO_PORT under %appdata%\ansys (copy and paste this in Windows file explorer address bar or in Windows search).
If that doesn't help, try deleting the entire %appdata%\ansys folder
If that doesn't help, refer to the question #7 in this FAQ document https://www.ansys.com/-/media/ansys/corporate/files/pdf/product/academic/student-faq.pdf?la=en
If that doesn't help, make sure you have read/write permissions under %appdata%\ansys