Note that the following instructions only apply to Sharetribe marketplaces.
Sharetribe marketplace users can create their account using their Facebook credentials. If users are seeing the following error, it means your Facebook App is not configured properly:
Given URL is not allowed by the Application configuration: One or more of the given URLs is not allowed by the App's settings. It must match the Website URL or Canvas URL, or the domain must be a subdomain of one of the App's domains.
To solve the problem, follow the instructions on how to configure Facebook Login and make sure that your domain is set properly in the Facebook App settings.