nginx: [emerg] could not build the server_names_hash, you should increase server_names_hash_bucket_size

This is most likely happening because of the long domain name. You can fix this by adding

server_names_hash_bucket_size  64;

at the top of your http block (probably located in /etc/nginx/nginx.conf). I quote from the nginx documentation what to do when this error appears: In this case, the directive value should be increased to the next power of two. So in your case it should become 64.

If you still get the same error, try increasing to 128 and further.

Reference: http://nginx.org/en/docs/http/server_names.html#optimization