I have seen a lot of issues regarding LaTeX being posted here and very recently i have noted one LaTeX. The \not\mid Symbol is not showing properly. It's showing like this: $p \not\mid q$. You may check this post: Importance of Cayley's theorem
As Rahul stated in the comment, we need to enable AMSsymbol to support
\nmid. However, what AMSsymbol does is simply assign
∤ (U+2224), so you could use the latter as a workaround now.
p ∤ q
$$ p ∤ q $$
See Tex \implies symbol does not work for detail.
This is completed as you can see here