Error 'Portal account owner must have a role' when you enable an External User

Root Cause

Salesforce requires that the Account owner has an assigned Role in the Salesforce Role Hierarchy when enabling portal or Experience Cloud users. Without a Role on the Account owner's User record, the portal user creation fails with the "portal account owner must have a role" error. This is a system requirement enforced at the platform level.

Manual Fix (UI)

To resolve the error when enabling a contact manually:

1. Navigate to Setup > Users
2. Find the Account owner's User record (e.g., the System Administrator user)
3. Edit the user record and assign a Role from the Role field
4. Save the changes, then retry enabling the portal or Experience Cloud user

Code Fix for Apex Test Classes

When writing Apex test classes that create portal or Experience Cloud users, use System.runAs() to execute the user creation as a user that has a Role assigned.
Approach:

1. Query a UserRole record (for example, the 'CEO' role)
2. Assign the queried role to an admin User record
3. Update the admin User record
4. Wrap the Account creation, Contact creation, and Portal User insertion inside System.runAs(adminUser) to ensure the code executes with the required Role context

This ensures that portal user creation in test classes does not fail due to the missing Role requirement.
(See Apex test class code example)

UserRole userrole = [Select Id, DeveloperName From UserRole Where DeveloperName = 'CEO' Limit 1];

User adminUser = [Select Id, UserRoleId From User Where Profile.Name='System Administrator' Limit 1];

adminUser.UserRoleId = userRole.Id;
update adminUser;

System.runAs(adminUser){
    Account a = new Account(Name='Test Account Name');
    insert a;

    Contact c = new Contact(LastName = 'Contact Last Name', AccountId = a.id);
    insert c;

    User user = new User();
    user.ProfileID = [Select Id From Profile Where Name='Customer Community User'].id;
    user.EmailEncodingKey = 'ISO-8859-1';
    user.LanguageLocaleKey = 'en_US';
    user.TimeZoneSidKey = 'America/New_York';
    user.LocaleSidKey = 'en_US';
    user.FirstName = 'first';
    user.LastName = 'last';
    user.Username = 'test@uniquedomain.com';
    user.CommunityNickname = 'testUser123';
    user.Alias = 't1';
    user.Email = 'no@email.com';
    user.IsActive = true;
    user.ContactId = c.Id;

    insert user;
}