I've been having this same issue. I tried reinstalling the software and going through the setup processes again but nothing has worked. I keep getting the error code 209: server disconnected. My PC is more than capable of running Beat Saber and it has been since June 2020. A couple days ago it just started happening and doesn't seem to stop. It happens with every VR game but I experience no abnormal statistics in my task manager during this or during any normal PC game. I've tried a different USB port and display port but that doesn't seem to fix it either. I sent a report to Vive and reinstalled all Vive related software.
My log report trace number is: 20210412143608
