What are the Steps required/identify the error or debug if project website is not responding

I have come across a question multiple time and I don't get any concrete answer of the question -

What are the Steps required/identify the error or debug if the project website on any env. is not responding

As per my understanding below we can do

1. First hit telnet comment to check if server responding Example:

   telnet your.server.name 80

2. Hit main API's to the respective website or test environment to check if API server responding as per expectation

3. Delete the cookies or browser / use private mode of browser / use any other browser and hit the website and check the network section to check if resources are downloading from source correctly

4. Check the website configuration file to check if everything pointing to correct resources.

5. At the end log into the website server and check the log to check if any error is present

Still, people don't look satisfy after all these answers. Is I am missing anything? please let me know your thoughts on same