Jitsi meet authentication error

Hello all !

I am trying to implement authentication when creating a room following this guide : https://jochen.kirstaetter.name/authentication-jitsi-meet/

I have managed to have the system up and running up to the authentication… and there when I try to login I have this error :

Sep 25 06:57:02 conference.meet.xxx.com:muc_domain_mapper	warn	Session filters applied
Sep 25 06:57:02 mod_bosh	info	New BOSH session, assigned it sid 'f2cdfc5d-2377-4614-bb9e-8d218bd2e50e'
Sep 25 06:57:02 http.server	error	Traceback[httpserver]: /usr/lib/prosody/core/usermanager.lua:108: attempt to index field 'users' (a nil value)
stack traceback:
[C]: in function 'parse'
/usr/lib/prosody/util/xmppstream.lua:271: in function 'feed'
/usr/lib/prosody/modules/mod_bosh.lua:136: in function '?'
/usr/lib/prosody/util/events.lua:78: in function </usr/lib/prosody/util/events.lua:74>
(tail call): ?
/usr/lib/prosody/net/http/server.lua:239: in function </usr/lib/prosody/net/http/server.lua:180>
(tail call): ?
[C]: in function 'xpcall'
/usr/lib/prosody/net/http/server.lua:112: in function 'process_next'
/usr/lib/prosody/net/http/server.lua:128: in function 'success_cb'
/usr/lib/prosody/net/http/parser.lua:177: in function 'feed'
/usr/lib/prosody/net/http/server.lua:159: in function </usr/lib/prosody/net/http/server.lua:158>
(tail call): ?
/usr/lib/prosody/net/server_select.lua:879: in function </usr/lib/prosody/net/server_select.lua:861>
[C]: in function 'xpcall'
/usr/lib/prosody/../../bin/prosody:400: in function 'loop'
/usr/lib/prosody/../../bin/prosody:431: in main chunk
[C]: ?

Is there something I am doing wrong or is this a real bug ?