I once again tried both login methods on both .com and .net. I'm not experiencing any problems.

Does it happen on more than one browser?

Does it still happen if you use a private/incognito window?

Does it still happen when connecting with a free VPN? Or if you we're already on VPN, a different server?

Can I assume you are connecting directly to https://konachan.com or https://konachan.net in an updated, modern browser?

I'm not sure what else to suggest.