From the main page, look at the top navigation bar. You will see links like:
Click Upload. This will take you to https://libgen.rs/uc/. Alternatively, type the URL directly. libgenrusec full
Once you hit enter, the results will appear in a table. Unlike the standard LibGen, the UC results show: From the main page, look at the top navigation bar
Solution: Your ISP or local network is blocking LibGen. You need the "full" unblocking toolkit: Click Upload