internal server error when remote room directory is private

[lub]

Description

When querying a remote server room directory which requires authentication, synapse currently just throws a {errcode: "M_UNKNOWN", error: "Internal server error"}

It probably makes sense to use a more specific error to indicate to the end user, that it's only possible to query that room directory as user of that server.

Steps to reproduce

• query /_matrix/client/r0/publicRooms?server=example.com, where example.com is a server with a non-public room directory
• get before mentioned generic internal server error

Version information

• Homeserver: imninja.net

• Version: 1.10.0rc5

• Install method: Docker

• Platform: Container

[richvdh]

related: #6325 ?

[anoadragon453]

@richvdh indeed

Both fixed in #6899

[lub]

Sorry, I didn't find the existing issue

[anoadragon453]

Fixed by #6899