というわけではない・わけがない・わけにはいかない: the difference
Meaning
It is not that, It doesn't mean that, It is not always the case
Past papers
Example
苦情という訳ではなく、提案です。
It isn't a complaint; it's a suggestion.
わけがないN3
Meaning
There is no way, There is no reason, It is impossible, Cannot be
Past papers
Tested 2 times in past papers
Example
彼が嘘をつくわけがない。
There is no way he would lie.
わけにはいかないN3
Meaning
Cannot afford to, No way, Impossible to do
Past papers
Tested 4 times in past papers
Example
僕はその問題を黙って見過ごす訳には行かない。
I cannot afford to silently overlook that problem.
How to tell them apart
「というわけではない」: a soft partial denial, 'it's not that...'.
「わけがない」: a strong total denial, 'there's no way'.
「わけにはいかない」: can't do it for reasons of duty or decency.
「わけ」 does a different job in each, which is a favorite exam point.