Any Site Link not working after Plugin Activation

Hi, very nice Plugin but on my site it causes this problem:

As soon as I activate it, clicking any link on the website will cause a redirection error.

In the address field of the browser it looks like this:

https://purelia.eu/index.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phprodukt-kategorie/index.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpndex.phpellness-salze/

Does anybody have any idea how to fix this?

Thank you so much!
Best, Jonas!

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