[ResponseOps][Connectors] Cannot create ServiceNow connectors with OAuth.

[cnasikas]

If you try to create a ServiceNow connector (ITSM and SecOps) with OAuth configured, the form displays an error about CORS, but the error is misleading. If you use basic auth, no CORS errors occur (assuming the SN instance is configured correctly). The UI form, when OAuth is configured, does not make an API call to api/x_elas2_inc_int/elastic_api/health. The call is important because it checks if the application is installed in the SN instance. Probably, this is why the error is being shown, and the connector cannot be created.

[elasticmachine]

Pinging @elastic/response-ops (Team:ResponseOps)