Override all permissions on spaces ends up in error

Issue Summary

The customer is trying to apply for default permission from Space Settings>Permission>Override all permissions but ends up in the below error.

Couldn't change space permissions
If this keeps happening, let us know at
support.atlassian.com

Usually, that's because when a space was created anonymously (by anonymous users) in Server, there was no creator set while creating them in Confluence Server and upon migration, the database didn't catch that information.

Steps to Reproduce

1. Go to the space in Confluence Cloud that you want to change permissions for 
2. Select Space Settings from the sidebar.
3. Select General from the Space permissions card.
   1. The Space permissions card is only visible if you're a space admin in that space.
4. Open the Override all permissions drop-down menu and select Default Permissions.

Expected Results

• The default permission should override the space permissions.

Actual Results

• Ends up in the error:

  Couldn't change space permissions
  If this keeps happening, let us know at
  support.atlassian.com

• And if checking in the console when overriding it shows something like:

HTT Header POST 200

<instance>.alassian.com/cgraphql?q=DefaultPermissions

And the response

java.lang.IllegalArgumentException: You are not allowed to add the SETPAGEPERMISSIONS permission to the anonymous user."

Workaround

The creator of the space can be updated in Cloud by an Atlassian Support Engineer. 

OR

Before exporting the space in Server, customers can check spaces that are without creator by running:

select * from spaces where creator is null;

and when with user_key, the creator can be updated by:

update spaces set creator = '<USER_KEY>' where lowerspacekey = '<LOWER_SPACEKEY>';