I Can’t do Multiple domains in the same cert using (Acme.sh) in Namecheap

Hello everyone I wanted to add a letsEncrypt SSL certificate with Acme.sh by going to the github documentation I ran the command
curl https://get.acme.sh | sh -s [email protected]
and it worked.
But when I type:
acme.sh --issue -d flata-tech.com -d www.flata-tech.com -d gestion.flata-tech.com -w /home/flatrbcg/public_html --force
I have this error:
gestion.flata-tech.com: Invalid status. Verification error details: 66.29.137.46: Invalid response from https://gestion.flata-tech.com/.well-known/acme-challenge/NG7dEzKCzZs4D7MciqpiAu5Y0ZXFJ2P96zFvcSKbxvA: 404
A note:
for my main domain it works very well the SSL is activated with the command:
acme.sh --issue -d flata-tech.com -d www.flata-tech.com -w /home/flatrbcg/flata-tech
i don’t know why it works with the main domain but not with the subdomains