Symptoms
Office 365 Subdomain Form does not work in the Online Store. The following message could be found in browser console:
{"Message":"No HTTP resource was found that matches the request URI 'https://10.1.1.2/O365App/aps/office365app/8bee0241-...614cb/checkAccount?accountId=1000012'.",
"MessageDetail":"No action was found on the controller 'Office365App' that matches the request."}"
Cause
Online Store customizations are not applied or done incorrectly.
Resolution
Perform all required steps from Office 365 Subdomain Form for OA Billing (OA Billing Customizations) KB article.