How to clear blockages on browser maliciously put there by someone else

[ronhem777]

I receive information from colleagues on the Internet with a link I must click on, when I click on this link it gives me a 400 bad choice.
How do I clear this blockage?

 

[Saga Lout]

If they're leading you into it, one of them must have put it there so tell them the fun is over and it's time to tell you how to get rid of it.