Improper "Wow this server is popular! Check back later to see if space opens up." error when trying to join realm.

Only 3 people currently in a realm, owner and two others. When I try to join as a fourth, I am unable to do so and get the "Wow this server is popular! Check back later to see if space opens up." 

 

Directly responding to an invite from the owner did not fix the issue, and neither did the owner leaving and me trying to join before them. Tried other fixes such as restarting minecraft and restarting computer, neither worked. 

 

Every time I click join realm I get "Loading resource packs" followed by the error.