Error code on Wordpress when trying to reuse an activity (download as .h5p file option)

Hi,

I'm running H5P on a Wordpress site. We have almost 300 activities shared but now we can't use reuse option (download as an .h5p file) because the code error message (see jpeg attached) appears instead of the downloading expected.

What can I do to fix it, please? I could not find anything and I think that just you could give me a piece of advise.

Thank you very much!