This was a problem we had moving a site from one domain to another using the Google Search Console Change of Address Tool.
The validation was failing with a 301-redirect from homepage failed, even though all redirects were working properly. Knowing the Google Search Console can be a bit finicky we gave it 24 hours, but still the issue persisted.
What finally worked was going back to the main Search Console page and using the URL Inspection Tool on the homepage we wanted to move, then running the Change of Address Tool again.
The Search Console throws up false positives from time to time such as ‘Text too small to read’ or ‘Clickable elements too close together’. Logging in and inspecting a page fixes most issues – even moving domains.
Now, all the old site’s URLs and organic history are redirected without hurting SEO and losing any website traffic.