Hi Murat,
Please run below commands and share the output (from all the nodes, if this is multi-node cluster).
show version
show interface
show cluster-nodeshow cluster-stateshow service
This command usually fails when cluster/node is out of service or any service is down in one or all of the nodes.
Regards,
Syamantak Omer
Syamantak Omer | Community moderator | Sr.Staff TSE | CWNA | CCNA | RASZA | RICXI