How to defeat file system error in Lenovo ix4-300d NAS?

Question

NAS

Hello!
For some time now, the Lenovo ix4-300d NAS has been getting the message "Errors were found in the file system of the Lenovo ix4-300d. Check needs to be done" on the "System Status" page . Disk parameters - a large file washer: 3 disks * 1.5 TB + 1 * 2 TB in JBOD mode. An attempt to perform an offline check of the file system followed by a reboot did not lead to anything - an error "Unable to update the requested settings" appears, followed by turning off the device. Can someone suggest how to overcome this error without losing data? It is possible to connect to the NAS via SSH.