Hi there,

I got following error on Set Your Org's External Org-Wide Defaults step.

Step not yet complete... here's what's wrong:
Your external org-wide defaults aren't configured correctly. Repeat the steps to make sure they are.

I tried with two new playgrounds.
Is there any other settings except below?

1. From Setup, enter Sharing Settings in the Quick Find box, then select Sharing Settings.
2. Click Enable External Sharing Model.
3. Click Edit in the Organization-Wide Defaults area.
4. For the Opportunity and Account and Contract objects, set the Default Internal Access to Public Read Only and the Default External Access to Private. Click OK if you get any popups or warnings.
5. Click Save.

<Trailhead : Share CRM Data with Your Partners>
https://trailhead.salesforce.com/projects/communities_share_crm_data/steps/set_external_owd

Thanks for any idea.
Regards,
LinThaw