[wpdm_tree] shortcode not working

I am having the same problem as was previously described here: https://ww.wp.xz.cn/support/topic/tree-short-code/

I have seen this issue posted on multiple other forums
https://www.wpdownloadmanager.com/support/topic/wpdm_tree-not-working/

I do not see what the final solution was in any of the similar cases I have found so far. Basically, the tree shortcode [wpdm_tree] will not work although other shortcodes work fine. I have the extended shortcodes plugin activated. Instead, on front-end I just see the shortcode itself. Can you publicly post the final solution to this so others running into similar situation in the future may know how to resolve.

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