From what I can see, this has been happening since at least 2017 very infrequently. The only post I have found so far with any helpful resolution is here: Server Timeout message displaying in every server
The only helpful guidance at the end of the post about a cause was:
“No sorry, I didn’t find out the problem, just that it may be caused by lag or an infinite loop calling the client continuously.
I haven’t yet found evidence of this but I would’ve put if I had any more info”
The only other advice was here, essentially saying to create a new place and transfer your things to that new place: People are getting kicked in my game for: Security Timeout - #4 by RafaNum24
That first post was in Engine Bugs, and since the issue is not visible to you, perhaps you could get more attention posting it there if you don’t find an answer here.
Hope this helps!