Sonoff S61S can´t be included anymore

Hi all,
I am using a Home Assistant Green and ZBT-2. 1 month ago I have integrated Sonoff S61S Plug In via “Including Matter Device” and it works perfectly (without any Integration or further Apps). SInce yesterday HA noticed that Sonoff is not reacting. So I have deleted, make a reset and tried to integrate again, but it failed. HA could not find the plug, while integration via Apple Home works. All other matter devices in HA works well. Can someone help me out? Thank you

Hi all,
I have realized that Matter Server 9.1 led to this issue. Once i made a back-up, it works perfectly. So I will discard this version and hope that programmers realized this issue and will release 9.2 where this issue is solved.