Unable to delete subscribes from the list

Hi,

I want to delete old subscribers, but nothing happens when I delete them.
They do not go to the trash, and those that were already in trash, can also not be removed.

As soon as I click on for example “non confirmed subscribers” my browser’s gives a message saying that this page is slowing down the browser, please stop this page. Seems like everything freezes and clicking on the trash tab, or others simply not works. This happens in Firefox and Edge too.

Any idea’s how to solve this?

Thanks!
Annie

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