Referenced entities switch.elektrische_deken_2_socket_1 are missing or not currently available

Check the history of your entity. If it’s going unavailable when your automation fires, then the action will fail.

There are two other issues I can see with your automation:

First one is an inconsistency - you’re using toggle to switch on, but turn_off to switch off. Try using toggle for both (and have a condition to check the state), or else use turn_on for your first automation.

Second issue is your trigger in the second automation - you’re using a time_pattern trigger, but what you really want is a time trigger. Learn the difference between the two or it might cause you issues down the line.

Finally, if you’re just starting out, I suggest you read this Why and how to avoid device_ids in automations and scripts. Again, learning this at this stage while you’re just starting out will help you avoid issues down the line.