[CMake] How to set CTest Update Options correctly

[NoRulez]

Hello,
i've set CTEST_UPDATE_OPTIONS as followed:

set(CTEST_UPDATE_OPTIONS "--tags")

I set this, because I need newely created and/or modified tags.

When I set this option then I get the error: 
"git.cmd" "fetch" "--tags" Update command failed

Is there an other way of doing so?

Thanks in advance

Best Regards