403 Forbidden Error After New Install

I’ve just installed Nextcloud to my Raspberry Pi 3, updated it, then turned on the web ui, but when I try to access the web ui, I get a 403 error immediately after clicking through the certificate warning. No login, nothing. I got the same result on Safari and Firefox. I’ve already tried adding nextcloudpi.local to trusted domains, but the result is the same.

It says “Nextcloudpi configuration v1.46.7” if that helps