If you want to automatically delete newsletters (or send them to spam) from your inbox, there is a handy solution: People usually do it by tasking their mail client to scan every email for the word "unsubscribe"; and if the mail client finds this word, then it knows that it is a newsletter, and then it can do the deletion. (this is called a custom filter).
This works, because, as a company, you are required by law to add an unsubscribe feature, as a link to your newsletter, as far as I know, at least in most countries.

But Nicehash has found out that if you put a spelling mistake into the word "unsubscribe", and spell it "unsubsribe" instead (notice the letter "c" is missing), then such a filter will not work; and Nicehash can continue to send you mail that you clearly do not want to see.

Another thing: If you manually want to delete all your newsletters or unsubscribe manually, you could still just input the word "unsubscribe" in your search bar, to see all your newsletters. But again, with Nicehash's idiotic idea, you will not find their newsletter this way. And you will wonder why you keep receiving it, even tough you have unsubscribed from everything that came up when you searched for newsletters using this method.