Entity not available in MQTT switch after adding (optional) configuration variables

Configuration
,
1

I add the following basic lines to my configuration.yaml file:

switch:
   - platform: mqtt
     command_topic: "/house/switch1/command"

This works fine; I see a switch entity in the Lovelace UI:
sshot-1

If I add one extra optional variable, like this:

switch:
   - platform: mqtt
     command_topic: "/house/switch1/command"
     state_topic: "/house/switch1/state"

I always get the message:
Entity not available: switch.mqtt_switch

It had always worked fine in a previous version, but it is broken now.
My current version is: Home Assistant 0.107.0.dev20200311

Hopefully someone is familiar with this problem and can help me out here.

2 
  - platform: mqtt
    name: "mqtt_switch"
    state_topic: "/house/switch1/state"
    command_topic: "/house/switch1/command"

Oh, you seem to have an extra character after mqtt

3

Thanks for your answer Francis.
In am a newie, and did not know how to insert code block, so was playing around.
First I use single line quotes, but changed it afterwards into block quotes because it lookes nicer.
By mistake I forgot to remove some signle line quotes, and correct this now in my original post.

So, with other words, the quote at the end of the line is not used in my configuration.yaml file and was not cause of the failure.

4

Yes, but if you don’t specify a name, how can HA find switch.mqtt_switch?

5

I also try to add the name parameter but this gives the same failure.
By the way, the basic one does not have a name and is dispayed correctly.