My robots.txt file is not updating

The module does not modify robots.txt. It controls robots meta directives on the relevant pages according to the NoIndex and NoFollow settings you select.

These settings are independent: noindex requests that the page be excluded from search results, while nofollow concerns following its links. Selecting one does not require selecting the other.

To check what your shop actually delivers, see the noindex verification procedure.

Important: blocking a URL in robots.txt can prevent Google from reading its noindex directive. See Google’s explanation.