@Dan?

It says that mod_rewrite should be enabled and I don't know if it is. That's why I need help.

https://www.opensource-socialnetwork.org/wiki/view/709/apache-mod-rewrite

It should be. Would you like a screenshot of the files?

are you installing this as root?

Cause that may be your issue, you need to ensure that your OSSN data directory, and the directories and files associated with your OSSN installation are writeable by apache.

When I do sudo a2enmod rewrite I get

(uiserver):u89574284:~$ sudo a2enmod rewrite

-bash: sudo: command not found

I'm sorry. I'm just dumb lol

sudo a2enmod rewrite
sudo systemctl restart apache2

Then proceed with your .htaccess config.

The instructions for Ubuntu and Debian are nearly identical... Like I said, I installed and ran it on my 1&1 with no issues, if this is the only thing running on your VPS, I'd suggest that you simply re-image to Ubuntu 16.04 as I can confirm for you that it works, I honestly haven't tried debian

@Dan It's not using Ubuntu though. It's using Debian I think. So how would I enable MOD_REWRITE then?

OSSN works fine on 1&1 - I have both the free instance and the premium instance working without issue. I strongly suggest using Ubuntu 16.04 on your VPS - And if you need php mail working, you'll have to call in and have them unblock port 25, other than that, no issues.

Follow these instructions:
https://www.rosehosting.com/blog/install-open-source-social-network-on-ubuntu-16-04/

@Roger Ok. But if there's a way I'm willing to try it. I also found this website which suggests that they will allow it. https://help.1and1.co.uk/hosting-c40985/scripts-and-programming-languages-c40990/htaccess-c41027/available-apache-modules-a792833.html