Step 3.1 not possible

[haerttrich]

By following the installation-guide, I get an following error message after running the commands from Step 3.1:

Cloning into '/home/user/haerttri/FGFA/incubator-mxnet/cub'...
Cloning into '/home/user/haerttri/FGFA/incubator-mxnet/dmlc-core'...
Cloning into '/home/user/haerttri/FGFA/incubator-mxnet/mshadow'...
Cloning into '/home/user/haerttri/FGFA/incubator-mxnet/nnvm'...
Cloning into '/home/user/haerttri/FGFA/incubator-mxnet/ps-lite'...
error: Server does not allow request for unadvertised object 89de7ab20167909bc2c4f8acd397671c47cf3c0d
Fetched in submodule path 'cub', but it did not contain 89de7ab20167909bc2c4f8acd397671c47cf3c0d. Direct fetching of that commit failed.

Therefore I cannot complete the installation, because the missing files seem to be essential for running make (as said in 3.2).
Is this Problem known? And what are possible solutions?