Although it looks like you’re using Cloudflare’s nameservers, both your naked domain and the tienda subdomain are resolving to 155.xxx.xxx.9 though:
$ dig elmercadoartesano.es
; <<>> DiG 9.16.27-Debian <<>> elmercadoartesano.es
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 43359
;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1
;; ANSWER SECTION:
elmercadoartesano.es. 149 IN A 155.133.195.9
$ dig tienda.elmercadoartesano.es
; <<>> DiG 9.16.27-Debian <<>> tienda.elmercadoartesano.es
;; global options: +cmd
;; Got answer:
;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 5500
;; flags: qr rd ra; QUERY: 1, ANSWER: 2, AUTHORITY: 0, ADDITIONAL: 1
;; ANSWER SECTION:
tienda.elmercadoartesano.es. 300 IN CNAME elmercadoartesano.es.
elmercadoartesano.es. 299 IN A 155.133.195.9
Your subdomain is a CNAME to your naked domain which is seemingly not proxied and is a gray-cloud.
The SSL certificate for your naked domain is invalid:
- elmercadoartesano.es » SSL Checker (sslshopper.com)
You need to resolve that with your Web host. As for the tienda subdomain though, it’s loading fine for me:
With that said, even if you do get 524 errors, you’ll need to resolve it with your Web host. Given that your DNS records are gray and not orange, traffic isn’t being proxied through Cloudflare and is direct to your origin.