Well, first: your default server may override your diaspora configs. In
nginx.conf, it’s a wise idea to put all your diaspora config after the two
include statements, or even better, write all your diaspora nginx configs into a file that gets included, for example
/etc/nginx/conf.d/diaspora.conf to make it easier to maintain.
You told certbot to create nginx configs for you, which conflict with what you are trying to do. You didn’t show the file names, but remove the files inside
/etc/nginx/sites-enabled that contain the last two server blocks, or to be more precise: the file containing the line
server_name www.iitians.xyz iitians.xyz; # managed by Certbot as well as the file that contains those redirects on the bottom. That’s all covered by your diaspora-specific configuration.
For future reference, please use three backticks to properly format your pastes, like so:
Otherwise, it’s a mess.