When I checked my drupal log entries, I saw error messages that files and images could not be found. The location and referrer of the error message indicated that the path of to the files were wrong. This was the result of the migration of my drupal site that i had performed.
I had first searched for hours to find the reason why the redirects were not working, I didnt recognise that these errors had also to do with the redirect.
I now perform a find and replace of the old and new file path and the taxonomy redirect is (also) working again.
Would be nice if the taxonomy redirect module displays a message to the user if the redirect fails, with the reason.