I have a quick doubt. Which is the correct usage of English, 'No issue' or 'No issues'? When we didn't get any issue, it represents null, so, ideally it has to be 'no issue'. Please correct me.
My guess is that you are referring to a predominantly Indian English expression, as a full sentence, which in other English dialects would rather be "No problem." (more neutral), or "No worries." (a bit informal). I understand that both "No issues." and "No issue." are frequently used.
Besides this, given the right context, there can be numerous examples for either "no issue" or "no issues" within a longer sentence, but in these cases the word "issue" is understood more concretely, as opposed to a general answer to sentences like "thanks for this" or "please do that".