Cannot replace existing realm

I created a Realms subscription yesterday.  I created a new world in it and played it.  Then I tried to create a new one and replace it, but received the following error message.   I am on an iPad Pro which is up-to-date with IOS releases and Minecraft version.

 

 

Steps to Reproduce:

1.  Click on create new world
2. Select game settings (I tried several different options to see if I could track down any specific setting, but no dice)
3. Click on "Create on Realms"
4. Under Choose a Realm, Select my Realm ""
5. Pop up appears noting this will replace current world, I press OK
6. Wait for a bit and then I get the attached error message