Hi Yosuke
Please contact A&H Technical support who will be able to help you resolve your issue.
https://allen-heath.helpserve.com/
Please include a detailed description of the problem. a copy of the Event logs and a show file, save a show with the system in the fault state.
It would also be useful for them to know if
you able to send audio from the Main L/R to the matrix ok with audio.
have you tried different output sockets?
Does the problem go away if you load a template show?
Regards
Sam A&H