Standard WordPress Search does not work / Search-results are not displayed / Custom template

The action field of the search form refers to https://startupsagainstcorona.com, which is the root of the web server.

However, apparently WordPress is installed at https://startupsagainstcorona.com/solutions, which is where the action field should refer to.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)