To Add on this:
I cannot speak for everyone else but in my case, in addition to not being able to access Realms...
1- Cannot Close the Realm down either
2- Cannot Switch Worlds
2a- This also means cannot access any of the "minigames"
3- Cannot download a backup to use on singleplayer
Related to REALMS-5600
Realm Servers are down, esp for Java. Other versions is a hit or miss.