Jicofo is stuck in "401 Focus request for room"

I have a problem happens randomly when users use the same room multiple times.

When I check Jicofo logs I find this line multiple times :
Jicofo 2020-04-24 09:57:09.765 INFOS: [89] org.jitsi.jicofo.xmpp.FocusComponent.handleConferenceIq().401 Focus request for room: myconference@conference.my.domain

It looks like Jicofo cannot create the room.

On the client side, I see this line in the JS console :
Logger.js:154 2020-04-24T08:23:04.915Z [JitsiConference.js] <e.sendMessage>: Failed to send a ping request or response.

is this a known issue ?