They never seem to work for me

Works for me (why I use it), but if you find a better NSFW host, I’d be interested. Catbox was the best I could find after imgur shoved their heads straight up their own ass.

this is honestly the first I’ve even heard of catbox, and idk how to just see images from it. it’s only giving me the option to log in or upload

There’s an official list on catbox showing governments and ISPs actively blocking it. You might be using one of these.

Seems to be working fine for me.

Seems to work normal for me, in the US, using Boost on Android.

It’s been interesting. I haven’t been able to get their videos to load from the thumbnail, but clicking the little + button that shows a post’s textbox will show the video and play it

… that is, until today. Suddenly the thumbnail expanding option worked.

OK so here’s the relevant F.A.Q.:

Why can’t I access Catbox/access files on Catbox (files.catbox.moe)? Good question! It turns out certain governments in the world hate freedom of information, don’t have net neutrality, don’t see online service providers as legally exempt entities, or a combination of the three! You will have issues accessing Catbox/files on Catbox if you are connecting from the following countries or providers:

Austrailia
    Why? - The Australian government had a heart attack after the Christchurch shooting, and decided that Catbox was a terrorist propaganda spreading website, and has instructed multiple Australian ISPs to implement DNS blocks of Catbox's domains.
    How to resolve? - Changing your DNS servers to a public server (i.e. 8.8.8.8, 76.76.2.0, or 208.67.222.222) or utilizing DoH should mitigate this problem.
Ireland/UK
    Why? - Unfortunately the love of footy has overtaken the sensibilites of the British and Irish governments, and they have decided to implement an IP level block on Catbox's primary IP address, due to clips of games being uploaded to Catbox..
    How to resolve? - You will need to utilize a VPN in order to evade this traffic hijack.
Iran
    Why? - Unknown, but I'm sure you can probably make some pretty accurate guesses.
    How to resolve? - You will need to use a VPN to bypass the IP-level block.
Afghanistan
    Why? - Unknown, but I'm sure you can probably make some pretty accurate guesses.
    How to resolve? - You will need to use a VPN to bypass the IP-level block.
Comcast/Comcast Business
    Why? - Comcast Business' "SecurityEdge" hijacking attack intecepts traffic going towards Catbox. Residential customers are blocked by "xFi Advanced Security" I have been unable to determine if this is a DNS level block, or an IP level block.
    How to resolve? - Comcast Residential: Disable the "xFi Advanced Security" hijack on your router. Comcast Business: Disable the "SecurityEdge" hijack on your account. See here.
Spectrum
    Why? - Spectrum's "SecurityEdge" hijacking attack intercepts DNS requests for Catbox for an unknown reason.
    How to resolve? - Spectrum Residential customers should disable the "SecurityEdge" hijack in their router/account settings, or use a VPN to bypass the hijack.
    Rogers
        Why? - Unknown. It appears to be dynamically filtering web traffic to Catbox.
        How to resolve? - Disable the "Advanced Security" hijack attack in your Rogers settings
    Verizon
        Why? - Unknown. This is a DNS based block, which means Verizon's DNS servers are returning no result for catbox.moe.
        How to resolve? - Changing your DNS servers to a public server (i.e. 8.8.8.8, 76.76.2.0, or 208.67.222.222) or utilizing DoH should mitigate this problem.
    Quad9
        Why? - Quad9 actually pulls an aggregate list of URL blacklists and uses them for their filtered DNS service. Catbox is frequently added to no-name blacklists for various reasons.
        How to resolve? - Use Quad9's alternative DNS server 9.9.9.10, or switch to another public DNS server.

I don’t think catbox content has ever loaded for me