I believe I'm also seeing this with the two branches I've tried to import on the LLVM project (https://code.launchpad.net/~vcs-imports/llvm/llvm-trunk and https://code.launchpad.net/~vcs-imports/llvm/clang-trunk). It's still trying, but there were some previous attempts ~1 year ago and they failed for the same reason, so I'm guessing those other attempts are most likely going to fail as well.
I believe I'm also seeing this with the two branches I've tried to import on the LLVM project (https:/ /code.launchpad .net/~vcs- imports/ llvm/llvm- trunk and https:/ /code.launchpad .net/~vcs- imports/ llvm/clang- trunk). It's still trying, but there were some previous attempts ~1 year ago and they failed for the same reason, so I'm guessing those other attempts are most likely going to fail as well.