I can't navigate in my lightbox : Cannot read properties of null (reading 'classList')

Hello everyone!

I’m having a problem, when I open my lightbox, the navigation and the images don’t work well.
I have the following error messages (for the previous and next element) : Cannot read properties of null (reading ‘classList’) .
So I guess the problem is my let element : ‘currentElement’ , but I don’t know why it is null.
Thanks in advance.

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