You do not know you know.

At no point is an agnostic and an atheist in conflict over knowledge, or lack thereof.  The agnostic knows of no god or gods, the atheist doesn't know either, the agnostic might be an atheist or theist, and the oddballs are those who think they're gnostic, or know that god is real.  Yet what is knowledge to them, a half-cocked idea of knowing via experience or faith, or pseudoscience and fallacies.  This isn't knowledge, even if it were true the knowledge or informational claim is false. 

As an atheist, I am saying I act acceptance of the claim, your god because I have not been convinced.  Other atheists may go as far as to say there is no god or gods, but they don't know this as an absolute, and the vast major of that group will not say they need absolutes in this regard because they're always ready to change their minds based on the evidence.  Real evidence, not magical proof claims. 

A theist of any kind will doubt rival gods, calling them false or even demonic, they believe and doubt in gods based on what they accept as true and will often use good arguments when pointing out the errors in a claim, but on when it's rival versions of the divine.  For example, they'll point out the frauds in hundu gurus worship and miracles but then fail to apply the same logic to their specific beliefs.  Even if there is a cross over between the claims made. 

A proclaimed agnostic, one who says they're not theistic nor an atheist is one who is normally atheistic but the label doesn't matter or is seen as too harsh to use for their opinion, often due to them not knowing the definition.  Agnostic as far as Atheism??  If they say that there isn't enough evidence to say god exists but I keep an open mind to knowledge that may appear then they're the same as almost any "militant" atheist.  

The key point here is we do not know, no special proof will do, and what some call "knowledge" is unfalsiable and so not knowledge.  If you nearly die and see a so-called "afterlife", but without knowing how reliable that is you know nothing than you did before such an experience took place.