It is not possible to log in to the WebClient. The following error messages appear:
Error during login: Unexpected token < in JSON at position 0
Error during login: JSON.parse: enexpected character at line 1
Probably the CORS configuration was forgotten. In the AdminClient, in the WebClient module, there is a button for the CORS configuration in the ribbon. This must be executed before the WebClient can be used. This stores a list of allowed CORS domains. Requests can then be checked against this list via the WebClient. Only if the origin header of a request is present in the allowed domains, the request will be executed successfully.
To add a domain, simply enter it at the bottom of the dialog. By clicking on the
the entry will be added to the top of the list.