If the search button is not redirecting you to the search results page check the following settings.
1. Make sure Permalinks are set to Post Name
2. Check the search results page template exists
his page is included with the theme activation, however, you may have deleted it by mistake. If it doesn’t exist, you just create a new page with the Advanced Search Results template.
You must have at least 1 page published with this Page Template (see highlighted in red)
Don’t set Advanced Search results as homepage.
3. Check the theme installation
If neither of the above work, check theme installation.
A wrong theme install (theme copied inside theme for example) will create duplicate page templatWordPressrdpress will not be able to know which is the correct one. The solution is to remove the wrong theme. Have just 1 theme wprentals in wp-content/themes.
You may need to edit all custom page templates and save them again after you correct the error.
To make sure you always install the theme correctly – check this help
To be sure you update the theme correctly, check this help