one Compile error base ubuntu

[cdkunsong]

refer https://github.com/mars-research/lvd-linux/wiki
mkdir build
mkdir cache
git clone https://github.com/mars-research/bflank blfank
cp bflank/config.cmake .
cd build && cmake ../blank
make
make driver-quick
make quick

when cmake ../blank

cmake ../blfank/
-- The C compiler identification is GNU 9.4.0
-- The CXX compiler identification is GNU 9.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Config: /home/work/bareflank/config.cmake
-- Bareflank Manager VMM
-- vmm: integration_intel_x64_misc_ept_enable_ept_static
-- target: integration_x86_64-vmm-elf
-- Including dependency: gsl
-- checking hash: 0cc95192658d10e43162ef7b2892e37a
-- md5 mismatch: expecting 0cc95192658d10e43162ef7b2892e37a, got d41d8cd98f00b204e9800998ecf8427e
-- checking hash: complete, redownload required
-- download file: https://github.com/Bareflank/gsl/archive/v2.0.zip -> /home/work/bareflank/cache/gsl.zip
-- download file: complete
-- checking hash: 0cc95192658d10e43162ef7b2892e37a
-- md5 mismatch: expecting 0cc95192658d10e43162ef7b2892e37a, got 41560f7d68373009d9867ea088f980a6
-- checking hash: complete, redownload required
-- attempt: 2
-- download file: https://github.com/Bareflank/gsl/archive/v2.0.zip -> /home/work/bareflank/cache/gsl.zip

are you know what reason ?
https://github.com/Bareflank/gsl/archive/v2.0.zip don't exist?

Thanks!
BR/SK