Some Questions to Networking:
1.) Can u use more then 64 Players for Networking?
2.) Can u do it via Blueprint
2.1) Tutorials please 
3.) Possible via code? (lmao i think i musnt even ask…)
3.1) Support for Copy&Pasters needed X3
3.2) An Tutorial would suffient enough to =)
4.) Are there some Files for an fully mmorpg?
4.1) Download or Site please =)
1.) Yes
2.) Yes
2.1) IDK
3.) Yes
3.1) IDK
3.2) IDK
4.) No, but there are some RPG open source projects for UE4, I think they dont support online for now.
4.1) Search on forums, somethink like rpg framework or somethink similar
The issue when wanting to make an RPG with unreal is not how many players it can support but its mostly server to server communication. Which would require custom coding based on your persistence layer. Other then that just becareful about how much bandwith you are using and dont go crazy cows with your replicated date and you should be fine.
Hi there G4merSylver, let me see if I can make easy:
1.) Yes, player cap is completely dependent on your game’s setup and the hardware it runs on. is true for most questions of scale (players, world size, polycount per object, etc)
2.) Sure can: Link
2.1) Another Link and an entire Playlist of Videos
3.) Yes, you have even more options to work with in code
3.1.) The next link should have some code snippets to copy/paste
3.2.) Code Tutorial: LINK
4.) Not really, MMO games are not very simple and can be tackled in so many different ways. Check out thread with a response from our CEO about it.
4.1.) I don’t really have anything for this, you may want to search the wiki and forums for more info. Making something as big and complex as an MMO involves a lot of trial and error.
For anyone reading because it says that unreal engine forums are closed, just use the wayback machine with the link.
Greetings @GalaCity !
We see that is your first time posting in our forums! 
On behalf of all of us here, welcome to the Unreal Engine Community! Thank you so much for your contribution to thread. It is members like you that keep our forums going strong! 