Widget area error

My client ask me to solve the following issue:

in the customizer page for managing widgets, it gives an error. The text for the error is the following:

TypeError: Cannot read properties of undefined (reading 'length')
    at p (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/block-serialization-default-parser.min.js?ver=eb2cdc8cd7a7975d49d9:2:1856)
    at f (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/block-serialization-default-parser.min.js?ver=eb2cdc8cd7a7975d49d9:2:1144)
    at i (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/block-serialization-default-parser.min.js?ver=eb2cdc8cd7a7975d49d9:2:759)
    at Fn (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/blocks.min.js?ver=69022aed79bfd45b3b1d:10:35954)
    at fe (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/customize-widgets.min.js?ver=1fddf6d27e5c3aeddd54:7:17581)
    at https://www.bedendoprefabbricati.eu/wp-includes/js/dist/customize-widgets.min.js?ver=1fddf6d27e5c3aeddd54:7:17924
    at Array.map (<anonymous>)
    at https://www.bedendoprefabbricati.eu/wp-includes/js/dist/customize-widgets.min.js?ver=1fddf6d27e5c3aeddd54:7:17916
    at Object.bt [as useState] (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/vendor/react-dom.min.js?ver=17.0.1:9:46710)
    at e.useState (https://www.bedendoprefabbricati.eu/wp-includes/js/dist/vendor/react.min.js?ver=17.0.1:9:10899)

I tried to disable all the plugin and activate just the theme, and the error is still there.

Could you help me here?

The page I need help with: [log in to see the link]