The API key and Device ID you have entered is incorrect.
The whole instruction is already provided in the training module - Project 6: Checking Device Status and Restarting the Device | Bolt IoT
The following statement is already mentioned in the text -
Please go through the training module twice before posting it on the forum. It’ll help you in correcting any mistake or doubt by yourself. Debugging an issue is a prime requirement when coding a program.
Let me know if you have any other queries.