Nginx and Certbot fails when trying to get certificates - nginx

Question

First of all thank you for your help.
The thing is that I'm having problems applying certbot to my site configured in nginx, I'm not an expert on the subject so I've been guided by a tutorial. Anyway, here are my settings:
clarify that the domain points to the IP and the site is accessible from the internet through port 80
/etc/nginx/conf.d/lexapp.es.conf
server {
listen 80 default_server;
listen [::]:80 default_server;
root /var/www/html;
server_name lexapp.es;
}
The command I try :
sudo certbot --nginx -d lexapp.es
The results I get :
Plugins selected: Authenticator nginx, Installer nginx
Requesting a certificate for lexapp.es
Performing the following challenges:
http-01 challenge for lexapp.es
Waiting for verification...
Challenge failed for domain lexapp.es
http-01 challenge for lexapp.es
Cleaning up challenges
Some challenges have failed.
IMPORTANT NOTES:
- The following errors were reported by the server:
Domain: lexapp.es
Type: unauthorized
Detail: 2a02:4780:1:753:0:3313:4df6:5: Invalid response from
http://lexapp.es/.well-known/acme-
challenge/ebE6_4SJ0B0yOIzWDyoIdWP0q0fZTldwteCaiORiBNo:
404
To fix these errors, please make sure that your domain name was
entered correctly and the DNS A/AAAA record(s) for that domain
contain(s) the right IP address.
I would appreciate any help