Simple can't access result page

Hello,

I hope you can help me. I don't have an idea why it's not working.

At my blog site I has a simple search box. http://cboehm.it/blog
Category is set to blog.

After press Enter the blog site will be reload but no search result appears. What could be wrong?

Thank you

Start by reproducing the missing-results behavior at http://cboehm.it/blog using the search box and the blog category setting. Then trace the SimpleSearch plugin's result-page flow and verify whether the query and category reach it. Done means a search submitted from the blog displays matching results; the issue does not name a file or test to run.

Written by the indexing model from the issue text.