If the sphinx service is started, but the search on the site does not produce anything (and an no error), the problem can be as follows:
systemctl status sphinxsearch
When checking the status of the service – pay attention to the line

...
... To enable sphinxsearch, edit /etc/default/sphinxsearch and set START=yes
...

In this case, just edit the file / etc / default / sphinxsearch and change the value of the parameter “START = no” to “START = yes”.
It’s all!