Password protected public conversation errors on password submission

[thurloat]

Steps to reproduce

1. make new conversation
2. set a password
3. open link incognito
4. enter password
5. HTTP 405 returned

Expected behaviour

guest user should be able to view and participate in the chat

Actual behaviour

server returns HTTP 405 (method not allowed). I'm assuming the router isn't allowing POST requests to submit the password?

Browser

tried FF and Chrome

Microphone available: NA

Camera available: NA

Operating system: Windows & OSX

Browser name: Firefox & Chrome

Browser version: FF 67.

Browser log

not a client side issue

Spreed app

Spreed app version: 6.0.0

Custom TURN server configured: no

Custom STUN server configured: no

Server configuration

Operating system: Ubuntu

Web server: Nginx

Database: PostgreSQL

PHP version:

Nextcloud Version: 16.0.0

List of activated apps:

https://hastebin.com/qavuyiyuzo.css

Nextcloud configuration:

https://hastebin.com/dutafequya.json

Server log (data/nextcloud.log)

relevant lines: no crashes or anything
https://hastebin.com/ehopetuyuz.nginx