Fix 421 Misdirected Request

You can execute these commands to do the change automatically:

for file in $(grep -l proxy_pass /usr/local/hestia/data/templates/web/nginx/*.stpl); do if ! grep -q proxy_ssl_server_name "$file"; then sed -i '/proxy_pass/ i\\t\tproxy_ssl_server_name on;\n\t\tproxy_ssl_name $host;' "$file"; fi; done
for i in $(v-list-users plain | cut -f1); do echo "Rebuilding web domains for user $i"; v-rebuild-web-domains $i yes; done

And for mail domains:

for file in $(grep -l proxy_pass /usr/local/hestia/data/templates/mail/nginx/*.stpl); do if ! grep -q proxy_ssl_server_name "$file"; then sed -i '/proxy_pass/ i\\t\tproxy_ssl_server_name on;\n\t\tproxy_ssl_name $host;' "$file"; fi; done
for i in $(v-list-users plain | cut -f1); do echo "Rebuilding mail domains for user $i"; v-rebuild-mail-domains $i yes >/dev/null; done

Credit to sahsanu