Japanese grammar question?

Question:

どうしても、漢字が思い出せない。

question is regarding せ　in だせない。shouldn't it be ださない？

Answer:

No. He's saying he CAN'T remember kanji. Thus, can't in a conjugated verb is root (das)+ enai ending.

If he was saying he DOESN'T remember kanji, then doesn't in a conjugated verb is root (das) + anai.