Suggestions do not work when Fess is installed under BASIC authentication

I have BASIC authentication applied to the entire site.
After passing BASIC authentication and opening the search page, the keywords are displayed in the search window.
When I try to type in a keyword, a BASIC authentication box appears.
I can’t type.
The suggestion function works and requests the server, but HTTP401 is returned.

Incidentally, Apache is running in front of FESS, and Apache performs authentication and forwards the request to FESS (localhost:8080) using ProxyPass.

Is it wrong to use FESS in this way in the first place?
I would appreciate it if you could enlighten me.