How to force httpS on file browser?

[digitimage]

Hi
I'm using El Finder as file browser for tinymce with this bundle in Symfony 5. It works great in local dev environment (even in HTTPS) but I get this error in prod environment:
The page at 'https://mydomain/admin/edit' was loaded over HTTPS, but tinymce.min.js requested an insecure frame 'http://mydomain/elfinder'. This request has been blocked; the content must be served over HTTPS.
Is there a way in config to force tinymce to call El Finder over HTTPS ?
Thanks
Cyril