I need to understand how to add header keys even though generally source keys are used. But many times I am unable to use a source key & idk how to get header keys. How do I figure out what to put like I've seen [ LOCATION>||invalid ] something like that. How do I know what to put for the header field? Also, some sites have notification bars or pop ups that tell you login is invalid. How do I get the keys in that? I am having that trouble now and I believe I need to use a header key. Would having a success key only without failure key be fine as well? Accounts that don't work would just go 'To Check' correct?