{ $scheme }: wildcard sources in ‘{ $directive }’ directives must include at least one non-generic sub-domain (e.g., *.example.com rather than *.com)
{ $scheme }: los orígenes con comodines en las directivas '{ $directive }' deben incluir al menos un subdominio no genérico (p.e., *.example.com en lugar de *.com)