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Try running nginx -t
Run yum clean all and try to update again.
Update all your ajenti and ajenti-v* packages.
.htaccess files are an ancient solution to URL rewriting problem. Recommended way is to use rewrite rules, both on Apache and NGINX. To convert your .htaccess to NGINX rewrite rules, use e.g. http://winginx.com/en/htaccess

Paste the generated set of rules into Custom Configuration of your website
This is now possible through Mozilla Persona auth support.