Why do the links to my models and tutorials give ERROR 404?

I put this link as an example, because I put it in an answer to another colleague's questions and he informed me that it gives him an error:

https://grabcad.com/library/linear-elasticity-1

When I enter this place from my profile there are no problems, but if I copy and paste this address (or use a link) it gives a 404 error.

PS: Nor do they get all the notifications of the questions that I follow, nor do they give me the scores when they accept or vote in favor of my answers.

PS2: it also happens with the followers, which sometimes do not notify me and they still do not appear in the list of notifications.