why creation of my diary failed?

Sometimes if you enter a wrong character into the environmental metrics. For example decimal points on a temp, even silly little things can cause error sometimes when trying to save, if its not working, try changing just 1 box each or add just one change each save until you systematically find what's causing the problem. Or it could just be bad servers. Please try again later.

some others have complained in questions recently, so maybe they are doing some sort of work on the site. try different browser, turn off extensions, and other typical troubleshooting options might help, otherwise. If you have exhausted what you can do on your end, you know it's a problem side-side.