Cannot ENABLE in Folder selection

[Hydroxyg]

In Library -> Folder Selection, while I press the "ENABLE" button, the toast shows the following message, and the document tree did not stretch as expected:

Failed to open: No Activity found to handle intent { act=android.intent.action.OPEN_DOCUMENT_TREE (has extras)}

I have only tried on build 853; 841; and 838, and seems they all have this problem. The only difference is that the older two versions would not show the toast.

I am on the latest version of the official system of Oneplus7Pro.

Could anyone help to solve this problem?