Problem with my ex2 ultra

hello

I’ve a problem its happends every i think four days one disk have red led i must do the restart of nas or turn off the power for the while. ive atached the print scren of the diagnostics panel.

The diagnostic page just relates that there was an error - to obtain more information regarding the error, press the yellow bell icon at the top of the page and a drop down menu will display more information regarding the error.