Forward-To protocol validation can be enabled by setting the property application.enableProtocolValidation to true. If you have this enabled please refer to the following step.
Forward-To protocol validation can be changed by editing application-docker.properties and modify application.validateProtocol. Default value is false and Forward-To URL will not be validated. Forward-To URL can be set like http(https,wss)://example.com or just example.com and the protocol chosen (from application-docker.properties) will be automatically set (it will be overwritten!)
Example: http://example.com will be wss://example if you chose wss in the properties).
If validateProtocol is true, then Forward-To header must contain full URL, including protocol.
Forward-To=localhost:8890/data - this one will fail, since it lack of information is it http or https
Forward-To=https://localhost:8890/data - this one will work, since it has protocol information in URL.