I just checked the jicofo.log files. And there was this error.
Jicofo 2023-03-10 11:02:41.406 SEVERE: [19] org.jivesoftware.smack.parsing.ExceptionLoggingCallback.handleUnparsableStanza: Smack message parsing exception. Content: '<conference xmlns='http://jitsi.org/protocol/focus' machine-uid='dedb7f016>org.jxmpp.stringprep.XmppStringprepException: wrong room name jid format
at org.jitsi.xmpp.extensions.jitsimeet.ConferenceIqProvider.getRoomJid(ConferenceIqProvider.java:202)
at org.jitsi.xmpp.extensions.jitsimeet.ConferenceIqProvider.parse(ConferenceIqProvider.java:74)
at org.jitsi.xmpp.extensions.jitsimeet.ConferenceIqProvider.parse(ConferenceIqProvider.java:39)
at org.jivesoftware.smack.provider.IqProvider.parse(IqProvider.java:40)
at org.jivesoftware.smack.util.PacketParserUtils.parseIQ(PacketParserUtils.java:555)
at org.jivesoftware.smack.util.PacketParserUtils.parseStanza(PacketParserUtils.java:113)
at org.jivesoftware.smack.AbstractXMPPConnection.parseAndProcessStanza(AbstractXMPPConnection.java:1450)
at org.jivesoftware.smack.tcp.XMPPTCPConnection.access$1000(XMPPTCPConnection.java:131)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.parsePackets(XMPPTCPConnection.java:972)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader.access$700(XMPPTCPConnection.java:916)
at org.jivesoftware.smack.tcp.XMPPTCPConnection$PacketReader$1.run(XMPPTCPConnection.java:939)
at java.base/java.lang.Thread.run(Thread.java:829)
Which changes the params that you pass to lib-jitsi-meet. Its is those params changed not adding a slash in the room name is the difference when using tenant for the room.