First Byte Time (back-end processing): NA

What does this mean? I normally get a letter but for some of my pages I am getting

First Byte Time (back-end processing): NA

I googled it an came up with nothing.

Do you have an example test? N/A just means that WebPagetest didn’t think it could calculate a grade but I’d like to see why.

Hi thanks for you for your reply. I have tested this same page numerous times and keep getting the same result.

Here is the test

the page being testing is

Looks like it’s an issue with Chrome SSL testing (specifically Chrome’s reporting of the timings) where the beginning of the test gets clipped so I don’t have a TTFB. It’s caused by some internal races in Chrome and dev tools doesn’t record accurate times in this case. It’s on my list to see if I can either fix in Chrome or find a better way to capture the data (likely the latter).