How to set Let's encrypt in ERPNext site using http challenge validation?

Hello,

Until now, I was using DNS validation for Let’s Encrypt SSL certificate.

Now I cannot use DNS challenge anymore, so I want to use http challenge. With this challenge, a file should be present in the disk and accesible using certain URL.

Where should I place that file?

I tried adding it to: /opt/bench/erpnext/sites/site1.local/public, but it did not work.

Any help, please?