xmlrpc 412 error

Good morning, I can not get the xmlrpc.php to work in wordpress, it gives me error 412, then I do not connect correctly Jetpack.

How can I fix it?
I do not know if it is a problem of cloudflare or wordpress.

I leave here some additional information about cloudflare:

• I have set “AS2635” to “Allow” to avoid firewall problems.
• SSL/TLS is set to “Full” mode.
• The “Always use HTTPS” option is disabled.
• The “HSTS” option is disabled.

I leave here additional information about wordpress:

• I have “All-In-One Security” installed and it has the option “Disable XMLRPC pingback functionality” checked, it does not have XMLRPC blocking enabled.
  On the other hand the plugin has a specific rule in the .htaccess: for the redsys plugin to work.

<IfModule mod_rewrite.c>
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteCond %{QUERY_STRING} !wc-api=WC_MyRedsys [NC]
RewriteRule ^(.*)$ https://%{HTTP_HOST}/$1 [R=301,L,QSA]
</IfModule>

• I have “Really Simple SSL” installed and “Mixed content solver”, “WordPress 301 redirect to SSL” and “Stop modifying .htaccess file” are enabled.

any solution?

Thanks

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