Err_Name_Not_Resolved Error Out Of No Where

Hi, we recently move our store to a new server, migrate and install everything, and it's working fine.

Out of no where, there is a few errors came out

1. 403 Forbidden error, manage to solve by changing file and directory permission

2. Modules not found, manage to solve by removing some modules in .htaccess


And we are stuck at here. Hosting that we use is AWS Lightsail, with Plesk.

The pointing of directory is fine, because when we put a txt file in our root, we can browse it. But when we try to browse a PHP file, then the error came out again.

We suspect is .htaccess or nginx conf errors, but couldn't solved it despite changing all the cong recommended online. Any pointers would be appreciate. Thanks!

It's a DNS failure. Either your hosting setup or the DNS server itself (Authenticated resolution).