Set user-visible error when the server is misconfigured.
Set user-visible error when the server is misconfigured.

rzr/synapse,matrix-org/synapse,howethomas/synapse,TribeMedia/synapse,matrix-org/synapse,TribeMedia/synapse,howethomas/synapse,iot-factory/synapse,TribeMedia/synapse,illicitonion/synapse,rzr/synapse,howethomas/synapse,TribeMedia/synapse,illicitonion/synapse,matrix-org/synapse,illicitonion/synapse,matrix-org/synapse,iot-factory/synapse,illicitonion/synapse,TribeMedia/synapse,illicitonion/synapse,rzr/synapse,iot-factory/synapse,iot-factory/synapse,iot-factory/synapse,howethomas/synapse,matrix-org/synapse,rzr/synapse,howethomas/synapse,matrix-org/synapse,rzr/synapse