I think time travel is impossible. All of the theories assume that the past still exists somewhere. And if you go into a parallel universe, and not into the past of your own universe, then did you really time travel? Right now, there is no future version of me popping into my room. So, if in the future, if hypothetically time travel was developed, and I deliberately chose this point in time to come back to, knowing I never saw myself in this point in time, how would that paradox be resolved? Are past/future versions of people conscious, since their current consciousness is in their brain/body in the present? The past, present, and future all existing at the same time would have to mean that every point is time is continuously and infinitely repeating itself an infinite number of times since you can keep "going back" to it over and over again. I think it's logically and scientifically impossible.
Time travel part two
the parrarel universes exist like they are like portals in time but people don't know how to open the portals
I do not believe in time travel. I think the imformation theory proves this ie if we can ‘travel’ to a previous point in time then we would be adding information to that point in time. Time travel and space travel to a different universe are sepeeate things for me.
If the information theory is disproven, I’ll be happy to meet my ancestors 
However, I see no logical paradox if the experienxers of a current moment in time meet a time traveler, just that I cannot comprehend how the time traveler could incorporate themselves in a different time such that it affects the future reletive to the destination. Its like a roller coaster but you try to bring a car from the middle to the beginning without altering the train of cars before and after it.
https://www.msn.com/en-us/news/technology/physicist-discovers-paradox-free-time-travel-is-theoretically-possible/ar-AA1lBPF3?cvid=f528e62307a34460ba0dafe2e25d0777&ocid=winp2fptaskbar&ei=18&sc=shoreline
Like I said in a previous forum post - Time travel is possible and by creating and branching off into a Parallel Universes, paradoxes are avoided. https://www.chess.com/clubs/forum/view/time-travel-13
In a parallel universe or multiple and probably infinte number of parallel Universes created by time travel, Stephen Hawking did meet time travelers! Just not in our universe.